Just like every other topic in this forum it turns into a 360 vs PS3
To the OP:
Uncharted
Assassin's Creed
Ratchet and Clank
COD4
Guitar Hero III
They are all solid games, with Uncharted and COD4 probably being the best. I would list Motorstorm but wait until January for Burnout Paradise.
Football games this year are average so I would stay away from them but if you have to choose one though your probably better buying FIFA as at least they seem to be able to finish a game and code it properly :X.
Seriously though, there are so many of these threads. Just have a look around the popular gaming sites, look at some video reviews and see what caters to your tastes.
There's a good selection of games to choose from but as of next year if a thread pops up in March it's going to be MGS4, MGS4, MGS4