Well, you need 2 troops and a HQ, so that's where you will start.
I suggest a Daemon Prince with wings, and 2 squads of 8 plague marines with champ + fist, and assorted special weapons. Like:
Daemon Prince, Wings, Mark of Nurgle.
8 Pm's, 2 Plasma
8 Pm's, 2 Plasma
8 Pm's, Champ + Fist, 2 Meltas
2 Oblits
2 Oblits
Total: 992/1000 points.
Simple and effective IMO.
It's a strong infantry base, and a beefy CC character, with some cover fire.
After that, you add onto the army other areas you will need, like anti-tank, anti-infantry, speed units, counter-attack units, assault units, etc. etc.
So, for cover fire, I then suggest obliterators, havocs.
For support for the army in general, raptors geared for cc are awesome, and zerkers are great in CC as well.
If you want to go Vehicle, you can give Rhino's to the PM's and fill out in the Hvy with those vehicles there.
Obviously, if you are every in doubt after adding Obliterators, MORE TROOPS IS BETTER, ALWAYS, ALWAYS, ALWAYS.
7 Cents from the 2007 Chaos Poster of the Year.
