Need Suggetion for buying new MP shooter.

Hi all @ Gamespot ,

Tomm is my b'day and I'm looking forward to buy a new MP Shooter.Please suggest a game with rich MP gameplay that I can still play on years after.

PS : Dropped COD,BF and MOH titles from my list, please suggest others apart from these ASAP.

BF3

any COD game

any Medal of Honor game

Counter Strike?

more info on what kind of experience you are looking for would be helpful