Gametrailers has their list.... here's MINE.
10. Turok - The N64 classic was better in Turok 2, but the original Turok had so many things that modern games simply don't have, ranging from dozens upon dozens of cheats and modifiers. But the sheer joy of killing dinosaurs as a badass Native American with a space bazooka is unquestionable.
9. The Darkness - Did I just sprout tentacles and eat the heart of a mobster? Cool!
8. Left 4 Dead - you, three friends, and a million zombies. Who's got pills?
7. Perfect Dark - In a just world, Joanna Dark would be as famous as Lara Croft and as respected as Mario. Sadly, Rare lost their minds and Perfect Dark Zero happened (the only game I ever regret buying). But the original? Amazing.
6. Bulletstorm - Remember when games were fun and didn't take themselves seriously? Bullestorm does. Have a hotdog.
5. Bioshock - Is a man not entitled to have a great story, pure gameplay, and a lack of multiplayer in his first person shooters? No, says the man at Activision; it needs more on-rails explosions. No, says the man at EA; it needs online multiplayer. No, says the man at Capcom; it more disc-locked content. I rejected these notions and chose the impossible. I chose... Rapture!
4. Half-Life 2 - Gravity Gun. Alyx Vance. Dog. Best game ever.
3. Team Fortress 2 - It's just pure insane wacky fun. It can get messy, but I dare someone NOT to have fun in a match of TF2.
2. Halo 1 - Halo 2 and Halo 3 may have evolved the formula, but something about Halo 1 just felt "right" to me. It felt tighter, more responsive, more skill-based. The pistol was the great equalizer, where skill with that starting weapon alone could tip the balance, long before instant-kill plasma swords and dual wielding was the name of the game.
1. Goldeneye - Yes, I agree with GT on this one. "Best shooter ever", probably not, but it's the best shooter I to me personally due to all the amazing memories I had. All those fun modes, all those clever gadgets, all those intense multiplayer matches... By far the best time I've ever had with a shooter.