Red Faction is a great game should try it out, haven't tried the second myself but I'm assuming it's good. The thing I love about RF is that there are no breaks, just one long continuous journey.
k:
Also Unreal 2 is an excellent game.
Jedi Knight 2 also.
Alien vs Predator is also pretty damn good.
Mafia is good although I never really got into it.
But Soldier of Fortune 2 would have to be one of the best.
k: