Call of Duty 2 is a good single player game, but the multiplayer lays in xbox live...
The only problem really with Call of Duty 2 is that the multiplayer can feel very stale when compared with a game like Perfect Dark Zero or Halo, because you can't really do much other than the same basic multiplayer options that have been used for the past decade. No vehicles, simple character selection, and basic weapons to choose from. The sad part is, this game really could have been one of the best FPS games ever if it had included bots and more multiplayer options.
Simply put, if you love FPS games and you own an xbox 360, go buy this game. If you aren't a huge fan of the WWII genre or you just don't like FPS games, don't get this game. I recommend getting Perfect Dark Zero just because the multiplayer can be fun for hours on end, and it provides more multiplayer fun than this game packs...