Dead rising, Crackdown are both platinum games now, must buys aswell
Condemned: Criminal origons is very cheap now but a fantastic game
Virtua fighter 5 and Virtua tennis 3 are worth investing in purely because the xbox 360 versions have online multiplayer and the ps3 versions don't
PGR 3 is now mega cheap but its a great racer
Rockstar table tennis is worth a go (it also has online multiplayer)
Saints row, Good game , well worth checking out before the sequel arrives
Ace combat 6 (360 exclusive and has online multiplayer)
Its a good time to be investing in a 360, especially with the great library of older games that are now at cheaper prices