I actually think the list is pretty good, although I would definitely swap in Halo 3 for Halo: CE, move Goldeneye to the top, replace Starsiege with Bioshock, mov-- actually, I'll just make a new list:
10.Unreal Tournament-=- (Even today this beast is entertaining as hell)
9. Doom -=-=-=-=-=-=-=-=-(Where would we be without Doom? Not that I ever really played it much, but I know how important it was)
8. Team Fortress 2 -=-=-=-(the best class-based multiplayer out there)
7. Left 4 Dead -=-=-=-=-=-(The best Co-operative FPS out there in my opinion)
6. Star Wars: Battlefront -(I played it in 1st person so it counts; here mainly for personal nostalgia)
5. Halo: CE -=-=-=-=-=-=-=(Revolutionised FPSes, for better or worse; brilliantly made shooter)
4. Half Life 2 -=-=-=-=-=-=("Wait, FPSes can have a STORY?!")
3. Bioshock -=-=-=-=-=-=-=(As a shooter it wasn't actually that great, but it taught me that a game could be ABOUT something)
2. Goldeneye-=-=-=-=-=-=-(my first FPS, important in its own right)
1. COD4 -=-=-=-=-=-=-=-=-(Probably my single favourite multiplayer ever made; I have plugged weeks and weeks into this game)