(ragnarok @ Mar. 13 2007,19:32)
QUOTE
So what focus should the list have, and what experimental stars should I use?
Actually, I'd say try some 2000 point games so you can, perhaps, get in a couple of "quick" games, perhaps even on a 4x4.
Have these guys played much EPIC yet? I'd almost recommend doing some Marine vs IG fights first, just to get the mechanics down.
If not, then just go with a basic army from 7.3.1, with none of the experimental stuff, with a good mix of Broods and Independents.
(Aside - if you're really doing a Tyranid invasion, I'd recommend taking a look at my "Attack" Phase list for initial planetary insertion!)