Star Wars: Knights of the Old Republic - I never play any game as much as SW:KOTOR(7 complete playthroughs, and several experimental characters I still play from time to time). This is The Star Wars Universe made new, with a story better than Episode I or II, that allows me to pick my path(good, bad, somewhere in between), allows me to choose my weapon(blasters, swords, lightsabers, the force), and keeps me wondering("what if I do this instead?"). Sure bigger games come along(Elder Scrolls IV: Oblivion, Grand Theft Auto IV) offering even more freedom(Fallout 3, Dragon Age Origins), but they don't measure up against the complete journey(story, music, gameplay) that is SW:KOTOR.