1. Fallout 3
2. Bioshock
3. Halo 3
4. Gears of War 2
5. GTA4
Many haven't played Bioshock, now is an extremely good time to pick it up seeing as it has been out for a year and still reamains ridiculously entertaining.
AND WHY ISN'T FALLOUT 3 ON ANY OF THESE TOP FIVE LISTS? You guys are nubs, that game had a great story, a vast expansive world, multiple side quests, and there are gonna be 3 expansion packs for it as if it wasn't big enough already along with a lift on the level cap. I've played 61 hours and I'm still finding new things to do, seriously, its been the best video-game purchase for me personally since I bought MGS3:Snake Eater, which by the way is currently my favorite game of all time.