10 - Command & Conquer: Renegade
9 - Metal Combat: Falcon's Revenge
8 - Call Of Duty 4: Moden Warfare
7 - The Conduit
6 - Metroid Prime 3: Corruption
5 - Red Steel
4 - Call Of Duty: World At War
3 - Perfect Dark
2 - Time Splitters: Future Perfect
1 - Goldeneye 007

1: Bioshock
2: Halo 2
3: Killzone 2
4: Halo 3
5: Halo: Combat Evolved
6: Resistance 2
7: Rainbow Six: Black Arrow
8: Half-Life 2
9: Resistance: Fall of Man
10: Timesplitters 2

In order:

1.) Doom

2.) Half-Life 2

3.) Bioshock

4.) Halo: Combat Evolved

5.) Timesplitters 2 & 3

6.) Duke Nukem 3D

7.) Goldeneye

8.) Team Fortress 2

9.) Call of Duty 1

10.) Quake

err....

Doom
Metroid Prime 3

That's it. I don't play much FPS.

1) Call of Duty 4
2) Halo 3
3) Half Life 2

You put The Conduit and Red Steel ahead of COD4?  Well, to each his own I guess...

10-Counterstrike

9-Halo 3 (honorable mention to 1 as well)

8-Goldeneye

7-Half Life

6-Metroid Prime

5-Freedom Fighters (I don't care that it's a 3rd Person Shooter, it still kicks ass!)

4-Perfect Dark

3-Timesplitters 2

2-COD4: Modern Warfare

1- Half Life 2 + Episode 2

I noticed a few people putting the Metroid Prime games in their lists. I have a hard time comparing those games to pure FPS, but if I did include those games, they would be right at the top of my list.

I haven't even played 10 shooters in my lifetime propably :P

1. Metal Gear Online
2. S.T.A.L.K.E.R
3. Battlefield 1943
4. Battlefield Bad Company
5. Counter-Strike: Source
6. Half-Life 2
7. Doom 3
8. Bioshock
9. Duke Nukem
10. Halo: Combat Evolved

wow I actually got 10

can't think of any more FPS games I have played

1. Call of Duty 4: Modern Warfare
2. Half-Life 2
3. Goldeneye 007
...
I haven't played that much FPS yet.