If you are gonna be a jack a$$ about it, then play whatever you want and leave us alone.
Black Templar - Dunno, my Tau have killed them repeatidly
Blood Angels - Dunno, but you WILL be called cheesy. CC specilists.
Sallies - These are my SM's. Good fluff. Simple color scheme. "Anything burns if you apply enough fire"
Dark Angels - I hate them. I reallllyyyy hate them, cause they wip my Tau every time (the kid who plays them is damn good.)
Space Wolves - Unique. 1 guy down here plays them, and they are nasty (Especcialy with their special character) However, photon nades really simplify things.
I think those are the big ones. Play what you want, if you want CC, get Wolves or Blood Angels. If you want long range death, go with Dark Angels. If you want death anywhere but in CC, go with Sallies. I am not sure about the others (haven't heard much abotu them, or played much.)
ORRRRR, you could go with Eldar or some other army and divirsity to the game (My other army is Tau)