Welcome to Librarium Online!
Ok, my best mate just got a necron army.
We are very competitive friends so we both want the best possible army to vs eachother, possibly even in 3 way battles [including another friends IG]
So my question is, with a monolith of 2 in his army, what is the best way to take on the necrons.
would rokkits work? in my current list i have 17 Lol.
please reply with some helpful advice and tips.
 Orks  Tau,
SM  WHFB Chaos
My buddy plays Necrons and the one game he faced my Orks we ended in a draw, but that was before he got his Lith. I've been thinking the same thing for the next time I face him, best ideas I've come up with are:
Basilisk - Str 9 Ordnance, against a Lith you still get the 2d6 take the highest for armor pen. The Demolisher is actually better for taking it out at strength 10, BUT it can't hide behind terrain and fire like the Lisk, so those Gauss weapons may take it out before you get a shot on the Lith.
Rokkits - 17 Rokkits you say, that's decent odds. If all 17 get shots on avarage 6ish are going to hit and 1 is going to glance. I'm thinking a strategy that contains a decent amount of Rokkits along with a Big Mek with a Super Stick bomb. My army runs with a Big Mek anyway, so the 5 points is a good insurance policy. If my Rokkits can atleast Immobilize the Lith than I can auto hit it with the Str 10 Stikk Bomb.
Only other option is to ignore the Lith(s) and go for the phase out. Get a fast squad to take down his Lord(s) asap and take out those Rez Orbs, then blast him away with those Rokkits and Basilisk.
Orks vs Necrons with a Lith all comes down to luck of the dice I think...
Monkey why in the world are you telling him to aim at the monolith. The 17 rokkits should be fired at the warriors and destroyers fool. Phase out, that is the way, I have never lost or drew against 'crons, the only thing I have killed one with is my beastly Warboss. If you get lucky enough, your best chance are killa kanz, 9 S10 attacks should get a glance atleast. The best monolith hunter are swooping hawks though.
2009 Tourny records (W-L-D) (20-4-4):
9/56, 1/12, 2/14, 4/14, 32/82, 1/6, 16/72
What is the points lever that you are playing at? With 2 monoliths he has to lack "necrons." Take a bassilisk and drop the pie plates onto the warriors. Get into combat with the warriors. Use enough that you win combat in the first round with the higher initive you should sweep. Sweeping advances don't alow wwb rolls even with a res orb. Close combat is what kills necrons. Get in cc quick. Take trukk boyz and get in a early charge to stop the warriors from moving a shooting. Trukk boyz are enough to hold up necrons and seperate those squads, unless the lord gets involed.
Remeber to forus fire, kill the whole squad never leave one alive never!
The monolith are just there for you to shoot and waste time trying to kill, ingore if possible.
Close combat is your friend force the necrons into cc they suck in cc.
Prey they don't take you alive
I'd say that you best bet is to take a large mob and foot slog it into CC. With each necron model costing 18+ points and orcs costing 8 - 12 points you should outnumber him enough to get in there and he'll be no match in CC.
His monolith can only teleport 1 group out of CC per turn so try and time your charge to hit multiple squads at the same time.
While I certainly appreciate the power of speed freaks, open topped vehicles against a necorns ability to glance is suicide... well most of the time. One exception would be if he fields 2 monoliths (or a mono and a C'tan). At this point the amount of models with gauss is much less and he can be easily phased out by a swift rush.
If an opportunity presents itself take out his lord. The lord is fairly weak (for an HQ), worth allot of points and can prove a pain if he has the right war gear.
Focus on "necron" models for the most part to phase him out. Scarabs are a huge pain as they can tie you up and/or strike down any vehicles you have, but they are weak to template weapons. Take them out with a few plates if the opportunity presents itself.
on hitting multiple targets at a time because he has monoliths, note he has 2 so he can teleport 2 squads back. so its better off mass firepower on one sqad at a time