After a while with Marines and Blood Angels I want to try a specialized army that isn't a MEQ, like Eldar or SoB. I don't want to do Hordes because of the time I need to commit to build and paint them. At this point I'm probably going for SoB, don't really care for fluff until after I've started the army (see my Blood Angels).

I find a Corbulo+Cannoness(with+2 I and Blessed weapon on charge) seem wonderful on paper, that would be 4 S6 I7 WS 4 Power Weapon attacks! That rivals Mephiston himself. Also I've considered an IG ally for the Leman Russ, what I'm planning is a IG battle force with the IG guardsman box, giving me as many guardsman as I need to take the Leman Russ, and 3 heavies for a better use for the guardsman.