COD is amazing IMO i cant believe i forgot to mention it
also
if your talking about xbox or xbox360
Halo 2 is the most popular.best multiplayer FPS out there for them
i could care less what you think about HALO 2
it still is the most popular FPS for the xbox and probably the most popular online multiplayer game for a console
if you like console FPS and have an Xbox, Halo is a most, wait for Halo 3 even its going to kill any other console game out there right nowor to come