This is it. Halo 2, the mother of all Xbox sequels. Well, it's all it's cracked up to be. The graphics are beautiful, the controls are flawless (as good as a non-mouse-keyboard combo can be), and the gameplay addictive.
The single player is very good, and you get into the campaigns very easily. The switches between perspectives from Master Chief to the bad guys is cool, and the single player ends up being a thorough introduction to the meat and potatoes of this game: the multiplayer.
Halo 2 shines in multiplayer. If you have Internet access, Halo 2 is probably the most fun you can get on an Xbox. Different level designs and game modes all ocntribute to make this one of the best multiplayer experiences on consoles.
Why no 10? Because of the ending, which is thoroughly unsatisfying.