Is Counterstrike the best online multiplayer shootem up? I adore it, but find Battlefield 2 much more engaging. And Call of Duty just has something more interesting about it. Rescuing hostages can get a bit dull.........
It's a matter of opinion, I used to play CS constantly but am now totally hooked on Unreal Tournament 3 beta, try it if you have time (and a fast system).
Trigger you should know better than that, no real gamers play Halo :p