-ADL with Quad Gun/Lascannon (depending on the BS of the guy firing).
-A delivery system for your troops (be that a transport, deep strike, infiltrate, scouts, outflank ect)
-Plenty of scoring units. With 5/6 Eternal War missions being objective based your going to want lots of potential units to hold them!
Without knowing your codex it hard to get into specifics.
This was a good response if your not after a specific codex.