If you want online multiplayer, then you should look at Unreal Tournament 2004, America's Army (free to download and play) or one of the many WWII games like Battle Field 1942 or Call of Duty. Far Cry is the first of the new generation of first person shooters, but is has a better single player game than multi player. For single player you could try Splinter Cell.
Fileplanet has demos for just about every game you could want and hundreds of mods and other extras. If you get a membership I think they still give you a free copy of Splinter Cell and you get much faster downloads.
goates