Is this top three favorite games, top three best games, or top three played games? For played, it's probably: 1. Rock Band 2 2. Grand Theft Auto IV 3. Halo 3 For critical acclaim, it's probably: 1. Grand Theft Auto IV (overrated) 2. Call of Duty 4: Modern Warfare 3. Gears of War 2
Only listing Xbox 360 exclusives: 1. Shadow Complex 2. Tales of Vesperia 3. Crackdown Shadow Complex is one of the best Metroidvania games I've ever played, the biggest flaw was the ending. Tales of Vesperia is a great Tales game (yes I know it's coming out on PS3 in Japan but as far as I know the PS3 version hasn't been announced for the US yet).. Crackdown is easily the best GTA style game I've ever played.
So many to choose from, but I'd say Fallout 3 is at the top of my list. 1. Fallout 3 2. The Orange Box (If I have to chose one probably Portal) 3. Either Crackdown or Burnout Paradise