Counter-Strike Source

[A Black Falcon]

Yes, I've played the demos of Half-Life, Half-Life: Opposing Force, and Half-Life 2. They seemed good, and have been on my list of games to maybe get someday since their releases. :)

Remember, here is a complete list of PC FPSes that I own (in order of acquisition):
Hexen
Star Wars: Dark Forces II: Jedi Knight
Star Wars: Jedi Knight: Mysteries of the Sith (expansion pack)
Star Wars: Dark Forces
Star Trek Voyager: Elite Force
Star Trek Voyager: Elite Force Expansion Pack (such an original name... )
Duke Nukem 3D (free full version from PC Gamer)
Return to Castle Wolfenstein
Tribes: Vengeance
Shogo: Mobile Armor Division (like $1, haven't played much)

... given that I have like 250 PC games, that says something about how often I play that genre... the only ones of those I've actually finished are Jedi Knight and its expansion, Elite Force, and Return to Castle Wolfenstein...