For me it would be The Witcher 2. Didn't have a PC to play it last year, so I opted for this year's 360 port. I was really blown away by the story, and even though I'm sure it is graphically inferior to its PC counterpart, I thought it looked phenomenal. It also played really well, loved the combat and the difficulty. Really top-notch game, if you haven't played it, it's probably pretty cheap and you should check it out fo sho.