Don't get Red Dead Redemption, Horrible no 1 is ever online.
If you want a good campaign, Dragon Age Origins is the best one I've ever played.
Grand theft auto 4. Nuff said.
Xbox 360 = BF2 / Crackdown 2
PS3 = Killzone
Wii = Super Smash Bros Brawl
PC = CS / MW2 / L4D2
preorder halo reach..that should be your best bet. unless you already did.