GTAIV
Dammit I wish I had more time to play GTA... In the first hour or two, the game actually wasn't the jaw-dropper I had expected (other games on the 360 definitely look better, and the walking controls are just as shitty as in the old GTA's). But boy has the game grown on me after a little while... there's not one session where I don't discover some hilarious shit to do in the game... there's so much attention to detail in the tiniest, most forgotten and dark corners of Liberty City... And some of the missions I have encountered so far are simply epic (the gunwork has improved dramatically over GTA3:SA, although the new cover system could have used a bit more work). Some of the elements I liked in San Andreas have been removed unfortunately (like the character development stuff), but all the new features and improvements definitely compensate for the loss. R* have delivered again.