What are your top ten favorite first-person shooters?

[snyperdud]

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