Should I get Rock Band or one of the Guitar Heros?
It depends as Guitar hero is just playing the guitar while rock bank allows you to play the drums, guitar and sing. I found them both to be good but wasn't all that great at singing or the drums so I mostly played the guitar.
Though Rock band is a hell of a lot more expensive due to all the extra equipment you have to buy so if you want to buy the cheaper of the two then that would be guitar hero.
I am thinking Guitar Hero, I'm trying to decide on the same thing.