1. Tom Clancy's Rainbow Six: Rogue Spear
One of the best, most engrossing fps I have ever played.
2. Half-Life: Counter-Strike
Still the pinnacle of competitive FPS gaming.
In 1998, this game taught me that FPS games can have a story and characters that I care about.
4. Starsiege: Tribes
The multiplayer in this was just...fantastic.
I had a tough time getting a lot of my computer related projects done because me and my friends were to busy playing Quake over LAN. A time before broadband is a scary thought.
6. Quake Live
Brought Quake to the browser, and brought something far more then a flash title to the browser.
7. GoldenEye 007
Still one of my favorite couch games.
8. Halo: Combat Evolved
Halo was the first console game that got us to bring our tv's together and have a console based lan party.
9. Battlefield 1942
64 player, WW2, vehicular slaughter and spectacular visuals for the time. This game had everything, the mods were phenomenal Desert Combat, Forgotten Hope and Eve of Destruction were worth admission on there own.
10. Medal of Honor: Allied Assault
This game defined epic for me in 2002, the multiplayer was also fantastic.
11. Call of Duty
Honorable mention goes to CoD, while the game currently is just barely a shadow of it's former glory I have a special place in my heart for this FPS. Always and forever CoD1...ilu.