The most competitive units are the Librarian
HQs, Draigo, purifiers w/ rhino, and the Dreadknight. Interceptors can be good too. A force weapon is a good pickup for the dreadknight, as well as both heavy weapons and definitely best of all the personal teleporter.
TEQs should get psycannons,
MEQs get incinerators. The codex is
TEQ heavy, but with the amount of AP2 in the game they're not point effective. Draigo is the guy who'll tank damage for you, better than a 5 man
TEQ squad and the cheaper
MEQ Strike Squad is exactly as capable as the
TEQs when it comes to stopping power. For a competitive list I'd go with one terminator squad or less. I'd even recommend the NSF detachment, which only requires one troop.
There
GK tactica discussion is here if you want to check it out:
http://www.dakkadakka.com/dakkaforum/posts/list/682457.page