This won't do against vehicles, so you do need a little help. Zoanthropes look amazing in this respect. Throw in a couple (but really, I mean 4) of them and, because I've seen how amazing the Mawloc model is, 2 Trygons. Make them Primes. Seriously. I'm not arguing with an 18", S5, AP5, Assault 12 attack. I think the 6" and 6 dice (and Synapse) are worth 40 points. Sure, BS is only 3, but it's 12 dice! You get 3+ to wound Marines and swarmy armies tend to get no armor save. And then they destroy stuff in assault. Extremely efficiently. For the HQ I'd probably go Tyranid Prime or two and stick him (or them) with Warriors.
The result is almost everything is Synapse, Ld10, and Shadow in the Warp, so they're a tough army to break. Anti-tank would do well against them with mostly T4 and 4+ saves, but that's what the Trygons and Zoanthropes would go for first. Zoanthropes, if you didn't know, have two main abilities (other than their 3+ invulnerable): Lance of Tank Popping and Blast of Marine Killing. Their main weakness is Grey Knight Psycannons or Incinerators. Anything AP5 or better that ignores invulnerables really.
Sample list I was playing around with in Army Builder comes in right at 2k:
2x Tyranid Prime (Boneswords, Deathspitter, Adrenal Glands)
2x 2-bug brood Zoanthropes
2x 5-bug brood Warriors (extra set Scything Talons, Adrenal Glands)
2x 5-bug brood Warriors (Deathspitter, Adrenal Glands)
1x 5-bug brood Shrikes (Boneswords, Adrenal Glands)
2x Trygon Prime (Adrenal Glands, Regeneration)
So basically I love super-resilient armies. When it comes down to it, running the Warrior list is probably a lot like running a Terminator Space Marines list. My two loves are Resilience and Mobility. I'll take an army you can pound on for 7 turns and not see it crack. But I'll also sacrifice all of that for one that can just zip around.