CSS is the best
but maybe America's Army is a good one to put on your list its a very realistic FPS, with very realistic graphics and gameplay, including medics, special classes, if u got hit u walk slower, if u jumped too high, u broke your leg, you walk very slow.
intrest go to
AMERICA'S ARMY: SPECIAL FORCES - HOME PAGE
or just me, i played it for over 2 years.
Cheers, Man!ak