Since Bioshock, the only First Person Shooter I've played is Medal of Honor: Airborne. I'm not really into these kind of games, but the two mentioned above, were kind of special. Both had spectacular graphics and MoH:A was very realistic.

Soldier of Fortune: Payback comes packed with realism. So much so, that it is actually full of gore. It takes the Shooter genre to the next level. Watch the two gameplay videos and decide for yourself if it's for you!