Empire:
I've been playing with these guys for about 10 years now as a secondary army. They've never really fallen out of favor with me, no matter what army I'm favoring at the moment, Empire is always there in reserves.
Movement- Average
Magic - Average
Shooting - Great
Combat - Average
General- the Empire are your stock standard army upon which all the other armies have been based. They include all major unit types with the exception of Monsters/Monstrous/Warbeasts although you could make a case for the STank and Character Mounts. They also have access to just about every weapon in the game with the exception of Short Bows, Bows, and thrown weapons, and have access to all 8 lores of magic.
Movement - M4, it's the average for everyone, Elves are faster, Dwarfs are slower, but M4 is pretty standard. They have options for scouts, fast cavalry, cavalry, and standard infantry. The only thing slowing down an Empire army is its predilection for Stand-and-Shoot weaponry, the two most popular ranged options being the Crossbow or the Handgun. This does not keep the army from moving, but with Shooting as it's strongest phase by far, most Empire generals are hesitant to bring the fight to the enemy any faster than they have to, even if they aren't playing an explicit "gunline". This isn't to say that the Empire can't march it's army forward and get into combat as quickly as other races, it simply means they usually choose not to.
Magic - Just like their movement, the Empire magic phase is bone stock. They don't get any special rules for casting or dispelling, they don't have any racial spell like Invocation of Nehek or the Dark Elf ability to create magic dice, they're right down the center. They get all 8 lores, and they get their level added to casting attempts.
It could be argued that their Arcane Item selection is rather weak, although they do have access to some interesting bound items like the Casket of Sorcery, which removes an enemy spell from the game, and allows the bearer of the Casket to cast the spell one more time. They have a definite lack of offensive casting augments. What they do have however, are Warrior Priests. These characters are one of the 4 main character types of the Empire. Rather than the usual Fighter/Wizard lineup of most armies, they have Fighters, Wizards, and then Priests and Engineers. The Priests each add 1 or 2 dispel dice depending on if they're a Hero or Lord respectively. They also carry with them a selection of bound spells which focus primarily on buffing the enemy. They don't have access to Arcane items, but mixed with the Empire's limited selection of Dispel-based items, it is possible for an Empire army to effectively lock out an enemy magic phase.
The best lore for Empire players is either Life, or Shadows, which are probably the two best lores in the game right now thanks to their ability to either raise units, or play a cruel buff/debuff game with your enemy.
Shooting - this is the Empire's forte. They boast a full complement of black-powder warmachines, and some of the nastiest. They have standard Great Cannons, but also have Mortars which are essentially Stone Throwers with a different misfire chart. Atop this, they stack a Helstorm Rocket Battery, which is a 5" S5 AP template weapon that is in essence a bigger, more catastrophic mortar. They also have Hellblaster Volley Guns. These guns are best employed as a defense for their other warmachines, as much of their infantry-based shooting is move-or-fire and therefore can't turn to engage outflankers or fliers who get behind the lines. Tossing 3 artillery dice per turn, this gun can put forward up to 30 S4 (S5 at close range) armor piercing shots, and wipe small units off the map.
Their Infantry-based shooting is no less impressive, offering Pistols and Handguns for their characters and infantry, with Handgunners coming in at less than 10pts each. They also have Crossbows, a popular option for covering the range gap between the 24" handgun shot and a 30" Longbow or Crossbow shot. The Empire does have access to Longbows, but being priced the same as the other two weapons makes them very unpopular.
The Empire also has Fast Cavalry carrying both a Brace of Pistols, or Repeater Handguns. RHGs are 3x Multiple Shot handguns, and are carried on BS4 Outrider fast cavalry, making them a deadly weapon indeed. Other weapons include the Hochland Longrifle, a 30" range handgun with the Sniper rule, available to Engineers and most ranged champions, as well as the 'Granade Launching Blunderbuss' which is a Knight-busting special weapon. They have repeating versions of their pistols as well.
Combat - the Empire boasts an average WS3, S3, T3 across the board. They have high-average Leadership of 7-8 on most units, an Unbreakable unit, and a Stubborn unit in their ranks. Unfortunately, they are limited to Light Armor and Shields on all except their Greatweapon armed unit and Knights. Their Knights however do have Full Plate for a base save of 4+ before barding and other additions. Characters are also allowed Full Plate. Unfortunately, Empire have a slightly-above-average points cost thanks to their Detachment System. This is a unique trait of Empire regiments, where certain units are declared as "Parent Units", and can take up to two additional units as Detachments. These Detachments can be no larger than half the size of the parent, and cannot have upgrades. However, they get some unique rules. If a Parent Unit is charged, the detachment can declare a Stand-and-Shoot and does not suffer the -1 penalty for their To Hit rolls. Combat-oriented detachments can declare a 'Counter Charge', immediately making a charge against the enemy as soon as they come into contact with the parent, and they are explicitly allowed to hit the flank. For this reason, Empire focuses primarily on Static-Combat-Resolution rather than raw killing power. The enemy should be suitably softened by the ranged units before getting into combat, allowing the Detachment System to carry the day.
In hindsight, the Empire are a decent army, balanced, and very flexible army. While they don't offer a point-and-click solution for a beginning player (other than the Gunline, which cripples tactical growth), they are brutally effective in the hands of a veteran gamer.
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Daemons of Chaos
My close friend plays Daemons, although he rarely fields them thanks to the stigma they've garnered and the fact that he has Lizardmen- a top tier army that has no such reputation. I've thumbed through the book on numerous occasions, played against them several times in tournaments with my Elves, VC, and WoC, and helped him build his tournament army as well.
Movement - Good
Magic - Good
Shooting - Poor
Combat - Great
General - DoC have long been regarded the most broken army in WHFB, because of their 'good' standing in every phase, and the opportunity to make any of those phases into 'great' by simply unbalancing their list.
Movement - Most Daemons range somewhere between M4 and M5, and they have representatives of both Fast and Monstrous Cavalry. What really elevates them though is their selection of flying units, like Screamers, and Flying mounts or flying abilities for many characters. The "Flying Circus of Tzeetnch" was a popular build before the current book, and although this has been slightly corrected in the current edition, they are still able to build some incredibly fast moving and very dodgy armies, which when combined with their magic or combat abilities, can have lethal results.
Magic - Daemons can't typically access the core Lores. They have their own lores much in the same way as Warriors, depending upon their character choices. Tzeentchian casters are brutal, and Tzeentch also features a core unit which counts as a caster based on the current number of models in the unit (Pink Horrors). This means that Tzeentch is almost always starved for casting dice, and they have no end of Wizards to use them on. They have major bonuses to casting with their Tzeentchians. Khorne on the other hand has no dedicated casters or lore at all, but they get Magic Resistance instead. Combined with an army-wide Wardsave, this makes Khorne units nearly impervious to spells which cause wounds directly, although many players complain that it no longer helps against spells like Dwellers, the Dreaded Thirteenth, or Infernal Gateway, which kill models outright with no saves of any kind.
Shooting - Shooting in a DoC army is limited to more Tzeentchian units really, Flamers, and Screamers (sounds dirty right? I know). Flamers are similar to a Skaven Ratling Gun or Dwarf Organ gun, in that they fire a random number of shots into the enemy. These shots are close ranged, but they are high strength and can be devastating. The Flamers themselves are a skirmishing regiment, adding to their mobility. The Screamers on the other hand have a unique "shooting-like attack" where they do damage to units that they fly over. That's right- they fly. They're not particularly good in combat, but they can make mediocre warmachine hunters, but the real bonus is that damage they do on the flyover. Screamers aren't usually regarded as a powerful choice though these days, because of the shooting attack isn't particularly powerful and it's all they've got going for them.
Combat - Combat is where all Chaos armies excel. You have different abilities for each of the gods, with the exception of the Tzeentcians, whose Pink Horrors should be kept out of combat at all times. Slaanesh features ASF, and Ini5, making them deadly foes indeed, their S3 is threatening when mixed with Armor Piercing characters. Nurgle features Poisoned attacks and Regen, which although plagued (no pun meant) with low stats all around, is brutal when fielded in the hordes as they were intended to be. Khorne is the most typical combat-unit, given that it's their god's specialty. They feature lots of attacks, made at a reasonable S4, and feature Killing Blow as a perk.
A note about DoC Characters - Daemon character cannot access standard magic items, and get "powers" instead. These are provided in their armybook, and are all quite good, although they're based on the Chaos God the Daemon represents. Characters of all the non-tzeentch gods are lethal in combat, tzeentch of course being a beast in the magic phase. It is also important to understand that characters can only join units aligned with the gods they represent, so it's not uncommon to see an army which focuses on just one or maybe two gods. This isn't a problem, as they all have defenses against each phase of the game, even Khorne can defend itself somewhat during the magic phase.
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Dark Elves
I recently looked into buying up my friend's Dark Elves after using them as a pickup army for the past 2 years or so. They're a good army, I've always enjoyed them although I hate the look of the older models, and I already own HE. They're very similar, quite literally the "Evil Twin" of the High Elf army.
movement - good
magic - excellent
shooting - good
combat - good
general - like Daemons, the Dark Elves are considered a broken army for being good at just about whatever they put their minds to. They are very similar to High Elves, in fact, many of their units are exact mirrors of the High Elves, even moreso now that ASF provides a Hatred-like Reroll. Dark Elves have Hatred army-wide, and so they get this reroll on the first turn of each combat, whereas High Elves get the reroll on every turn, under the right conditions.
Movement - Like High Elves, they feature all of the basic movement types of Infantry, Cavalry, Fast Cavalry, Skirmishers etc, and are all M5. It should be noted that their Cold One Cavalry (between Silver Helms and Dragon Princes) is a bit slower thanks to a lower movement and Stupidity. The difference though is that Dark Elves have access to core fast cavalry, and it's probably the best fast-cav unit in the game thanks to its Repeater Crossbows and high leadership, making it easy for them to Flee! charges and subsequently Rally.
Magic - Dark Elf magic is brutal thanks to its ability to manipulate the Power Dice pool, and their lack of a 6-die cap when throwing spells. For this reason, Dark Elves can keep tossing forward a magical onslaught until their heads explode or they run out of targets. With an item that sacrifices friendly models for dice, and a racial spell that generates D3 additional dice at any time in the casting phase, they are able to turn 12 dice into a whole more. Their magic lore is pretty basic, on par with most of the other "Dark Lores" like Death and Shadows, (which they can also take), it's just the fact that they can toss so many spells that makes them such a threat.
Shooting - Repeater Crossbows. Yep, nasty weapons. S3, and in the hands of BS4-5 models with 2x Multiple Shots, Move-and-Fire, and slightly diminished range. These weapons are terrifying for lightly armored enemies, and are capable of laying down some hurt on heavy armored ones as well thanks to sheer weight of fire. They have the exact same Bolt Throwers as the High Elves, but at a 2-for-1 unit cost, so they tend to have twice as many if they'd like. It's uncommon to see many Bolt Throwers though, just because they compete for space with the Hyrda, which we'll get to in the next phase.
Combat - Like the elves, WS5, Ini5, S3, T3, and they swap ASF for Hatred. Lots of Light Armor, Heavy is the best they'll get. What makes them different is that they have the Hyrda, which is one of the best monsters in the game, and is the most under-priced, making it the clear choice for all your mayhem-inducing needs. A Monster and Handler with elevated toughness, 5 wounds, and a Regen save (on top of a decent Scaly Skin) this thing's a beast in CC. Wyches and Shades are also good, provided they make it to combat alive. Assassins are also downright hellish. Similar to most other races characters, but without all the leadership and BSB perks, Assassins can be equipped with all sorts of devilish items that make them excel at either butchering enemy RnF troops, or slicing through enemy characters with ease. There are several armies that rely so heavily on their Assassin's prowess, that the rest of the army is really just an Assassin delivery. The best(worst) part? Assassins hide in any Dark Elf unit, meaning that you never know where your opponent might have one lying in wait. You will also hear speak of the "Reverse Wardave" lord and how difficult he is to actually kill. While not intrinsically good at combat, the Dark Elf lord has the option of carrying a pendant which grants him a variable wardsave. Basically, he only needs to roll equal or under the Strength Value of the attack that killed him (6 always fails). Combine this with a model riding a very tough Dragon, and you see the problem: you want to send in monsters or high-strength models to deal with the Dragon and score easy wounds on the rider, but his Wardsave turns into a huge bonus for him.
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Well, there you go Reiko, knocked out 3 armies for you, hope this helps, and I hope the thread comes back around. If anyone wants to contest my points with any of these armies, feel free. My standard WoC or HE were already taken and explained quite well, so I figured I'd use my knowledge of the other armies to help fill in some gaps.