Free First person shooter for PC with a good single-player campaign?

I already have some good games for online mutiplayer, but would lke a good single player game.





I already have:





Prism: Guard Shield


Smokin' guns


Alien Arena


CrossFire





Any suggestions?Free First person shooter for PC with a good single-player campaign?
Here are a couple of good ones:


Far Cry: http://www.gamershell.com/download_20867鈥?/a>





Full Spectrum Warrior: http://news.bigdownload.com/2008/10/07/d鈥?/a>





To the other Answerer, he said free...Free First person shooter for PC with a good single-player campaign?
Call of duty 4 modern warfare is multiplayer heavy (thats what you always see and hear about) but it also has one of the best shooter campaigns since halo CE

tvs