I just had a 1500 point game against DE. Here's the army I used:

Hive Tyrant:
Adrenal Glands (WS), Toxin Sacs, Extended Carapace, Enhanced Senses
Scything Talons, Venom Cannon
Catalyst
2 Tyrant Guard

Tyranid Warriors (x5):
Adrenal Glands (both), Toxin Sacs, Extended Carapace, Leaping
Scything Talons, Rending Claws

Genestealers (x8):
Extended Carapace

Genestealers (x8):
Extended Carapace

Genestealers (x8):
Extended Carapace

Guants -- Spinegaunts (x20):
Spinefists

Guants -- Spinegaunts (x20):
Spinefists

Guants -- Spinegaunts (x20):
Spinefists

Ravener (x1):
Scything Talons, Rending Claws

Ravener (x1):
Scything Talons, Rending Claws

Ravener (x1):
Scything Talons, Rending Claws

Zoanthropes (x2):
Synapse, Psychic Scream

One Venom Cannon and lots of Spinefists. Fortunately, he didn't have any vehicles. Otherwise, my Tyrant might have been a major priority for killing. As it was, it rarely got shot. The Zoanthropes don't have Warp Blast because they rarely hit with it anyway.

My deployment placed the two Zoanthropes in the forward-centre of my deployment with an 18" space between them. The right-hand Zoan was closely flanked by two Genestealer squads, the left-hand squad was surrounded by the last Genestealer squad. The Warriors were right in the middle, with the Tyrand close behind. Two Spinegaunt squads were deployed in the rear on the right half, while the last was deployed on the far left, beside the Genestealers. One Ravener found a space near the Warriors and the other two were on the far right flank by some woods.

His army consisted of two Taloses, a walking Archon and Dracon with the standard fixings, a squad of 10 Wyches (the Succubus armed with an Agonizer) that rolled "Re-roll misses" for their drugs, six 12-man Dark Lance Warrior squads, and an 8-man Scourge squad with Dark Lances. In all, 16 Darklances.

His deployment was fairly simple. The left (from my point of view) flank and centre were packed with Warriors, though they weren't deployed fully 12" from his board edge. Instead, they were about 4" back. On the right, one Warrior squad was fairly close to the edge. One Talos squad was further behind that Warrior squad and the other was just to the right of it. The Scourge squad held the rear center and was flanked on the right by the Wyches. His Archon and Dracon were in the right and left centre respectively.

Turn 1:
I went first at the start of the battle and everything charged forward. The Ravener on my far right flank strayed even further to the right into the woods, in an attempt to get into a position to charge a Talos without having to charge through cover. I rolled quite good in their fleet-of-foot rolls, and other units faired mediocrly. The Tyrant, my only long range shooter, popped a couple Scourges.

His turn was entirely static. He stood his ground and fired. After a couple squads managed only a single wound on my right-hand Zoanthrope, he gave up on it and started shooting Genestealers. One squad was wiped out by the rest of his shooting and a couple Gaunts were popped by the Taloses.

Turn 2:
In my next turn everything charged forward once again. I popped another Scourge with my Tyrant and the Raveners charged into a Talos. With their ten attacks, they managed two rending hits and suffered one wound in return. The right-most Genestealer squad, manged to get within range to charge his right-most Warrior squad. They killed a bunch, forced them to flee, cut down the rest in the Sweeping Advance, then consolidated into the wounded Talos.

On his turn another Genestealer squad was blasted down to 2 and a Warrior took a wound. Other than that, perhaps a couple more Gaunts were killed and that was it for his shooting. The combat that currently continued on the right was joined by both his Archon and Dracon, and the Wyches. His free Talos didn't participate, but had parked itself just to the left, facing down an approaching squad of Spinegaunts. One Ravener was killed by the Archon (who with the Dracon took a wound from drugs), the two Genestealers in base contact finished off the wounded Talos, and the Wyches killed a couple Genstealers, who unfortunately did little in return.

Turn 3:
My next turn! Charge! On the left and in the middle, two Spinegaunt squads fired. The middle squad of Warrior that was shot was forced to flee, but remained on the table. The Scourges took more wounds, but remained in place. The two Genestealers that remained on the left charged into a Warrior squad, forced it to flee, killed it in Sweeping Advance, then consolidated into a damaged Warrior squad. The Spinegaunts on the right flank charged into the Wyches and the remaining Talos (mostly to prevent it from charging them the next turn). Things weren't going well at all, on that side. The Genestealers were almost finished, the Spinegaunts doing more damage than they. Fortunately, the Talos managed on a single kill. The final Ravener died to the Archon.

At this point, his shooting improved slightly, but he had much less of it. Two squads were dead, one had just regrouped, and another was in combat with Genestealers. Finally, though, he manged to kill two more Warriors and delt a wound to another. Due to some odd line-of-sight issues, only my Tyrant was visible and took two wounds. The combat on the right saw the end of the Genstealers there and some more Gaunt deaths. Once again, the Talos did poorly. The two Genestealers on the left did nothing, but received nothing in return. The Warrior squad that had regrouped managed to fleet of foot and charged into my centre Spinegaunts. They managed to kill about a third, but took heavy damage in return. His Archon killed the wounded Zoanthrope on the right.

Turn 4:
Finally, the Scourges fled after being shot up some more. My left Gaunts charged into combat to help my Genestealers. Together, they finished off that squad and consolidated into the next. The centre Gaunts and the Warriors they were in combat with were joined by my remaining Zoanthrope. My own Warriors, which had been slowed by difficult terrain and then blocked from combat by a wall of Gaunts, aimed to the right and, charged by Catalyst, assaulted the Archon. They managed no wounds and took to in return, leaving one healthy and one wounded. The gaunts engaged with the Wyches, the Dracon, and the Talos were finally finished.

His turn saw his one free Warrior squad deal a single wound to a Tyrant Guard. The squad on the left was destroyed by the Gaunts and Genestealers, but only one Genstealer remained, which consolidated to the right. The DE Warriors in the centre were finished by the Gaunts and Zoanthrope, while my Tyrant was assaulted by the Talos, Wyches, and Dracon. I lost a Tyrant Guard, but killed the Dracon. His Archon finished off another Warrior, leaving one wounded and taking a single wound in return. The Shadow Field had fallen.

Turn 5:
My left Spinegaunts and Genestealer charged to the right, to the remaining Warrior squad. The Spinegaunts killed a fair chunk, the remaining Warriors holding their ground only to be assaulted by the Genestealer. They lost combat, were forced to flee, and were cut down in the Sweeping Advance. The centre Spinegaunts rushed to the right to aid my last remaining Warrior. The Archon killed it, but was without his Shadowfield and died easily to the charging Gaunts. Meanwhile, my Tyrant killed more Wyches and forced them to flee. Still in combat with the Talos, no Sweeping Advance occured, but the Wyches were below 50% and had no chance of regrouping. The Talos took a rending wound and delt on back in return.

At last, we called the game. His Talos was all that remained, but it had only two wounds left. It still had to kill a Tyrant with two wounds and a Tyrand Guard. Beyond that, a Genestealer and a Zoanthrope were approaching. With the Wyches there had been a chance, but alone the Talos was doomed. If the Tyrant were killed, the lone Genestealer wouldn't last long. After that, I would have nothing to kill the Talos. The Wyches were gone, though, so there remained no point in continuing.

Conclusion:
I haven't actually won very many games against this DE player. This time, he regretted taking so many Dark Lance squads. Another squad of Wyches would have done much more. At the very least, my Spinegaunt squads wouldn't have had so much free reign. Still, it was quite close up to that last round.

My Spinegaunts were easily the most helpful units in the game. They were devastating in close shooting, had the numbers to eat a large number of enemy attacks, and had the mass to lay on a heck of alot of attack by themselves, especially on the charge.

A close second would be the Zoanthropes. Their largely passive involvement kept units from fleeing, yet at the same time making it much more difficult for enemies to pass morale tests. They were twice as good as when they had Warp Blast -- and were cheaper, too.

The Genestealers soaked up plenty of firepower. Most of the Darklance shots were directed at Genestealers and while they took heavy losses, the remainder still did a decent job. Even the one on the right, which did pitifully against the Wyches, managed to destroy a Warrior squad and finish off a Talos.

My Tyrant and Warriors were the most unfortunate, having been slowed by difficult terrain and then blocked from combat by their own army. In the end, though, they held their ground with the tenacity that is to be expected from them.

The Raveners. . . were a distraction and otherwise performed unimpressively. They did serve a purpose, but unfortunately couldn't kill anything. They held the Archon for a turn and did some damage to a Talos. Actually, I forgot to mention what happened to the third Ravener. Well, it died without even making it into combat. *sighs*