I'm listing these according to the recommended playing styles
-->Urban Terror : free, fast and addictive if you get a hang of it
-->Counter Strike : Campers FTW
-->CoD:Have a lot of variation but teamwork is not required always
-->BF BC2:Better than CoD if your main focus is on teamwork
-->Team Fortress : Haven't played it yet but all I can say that it is one of the epic game with loads of fun.10/10