Wich FPS shooters can u advice me for online multiplayer ?

Played a lot of CS 1.6 & is still got a big community.

But in 2 weeks got a new pc and like 2 play BF2142 etc..

Don't know wich games got a nice amount of people playing and not laggy.

Hopefully MOH:Airborne and CoD4 wille be hot online.

Oblivian isnt online i think eh??:( (Know its RPG)

Thnx in advance :D