What is a good xbox 360 game

A good place to go is GameSpot.com (Not GameStop) and look at their highest rated xbox 360 games. That tends to be a good guide. A couple of the really popular games are Halo, Gears of War, Call of Duty: Modern Warfare, Assassin's Creed, and Grand Theft Auto 4, but there are a LOT more than just those.

dont forget modern warfare 2