10. Devil May Cry 3 (PS3)
The epitome of great hack-and-slash games, with one of my favorite protagonists in any series. There's something about the way that this game controls that just feels natural. And skating around on a demon with two blazing handguns after running up a wall is just badass. By the way, the list of difficulty levels is borderline ridiculous.
9. Warhawk (PS3)
One of my favorite games to play with friends, and a great third-person-shooter, as well. I'll really miss this one when the servers go down...
8. Silent Hill 2 (PS2)
One of the best stories I've seen in a game thus far, coupled with Silent Hill's trademark creepy atmosphere. Despite James being an outwardly flat character, the depth and development of both him and every other character in the game is nearly perfect. And Pyramid Head.
7. Carnivores Cityscape (PC)
Despite some of it's flaws, one of my favorite FPS games, with surprisingly great atmosphere. And dinosaurs are cool.
6. Shadow of the Colossus (PS2)
A fantastic adventure game with an atmosphere of both colossal epicness (I hate to throw that word around, made up or not) and vast emptiness. It also has a surprising story/character depth, for a game with a near-silent protagonist and very few characters. And the music is very fitting and pleasant to listen to.
5. Sonic Adventure 2: Battle (GCN)
So bad/cheesy that I can't help but love it. Crush 40 makes it all the better, and even the multiplayer is enjoyable.
4. Luigi's Mansion (GCN)
Probably the game I've beaten the most times, granted it isn't all that long. There's something I love about this game's atmosphere, as well. It's very different than any other game in the Mario series, and I think that factors into its charm.
3. Resident Evil REmake (Wii)
My favorite game from one of my favorite series, with one of my favorite villains and one of my favorite supporting characters. And once again, atmosphere, largely because of the flesh-eating monstrosities but also because of the soundtrack.
2. The Legend of Zelda Twilight Princess (Wii)
Another of my favorite games from another one of my favorite series. I love OoT and MM as much as the next guy(/gal), but there's something about this one (nostalgia?) that puts it on top for me. Twilight Princess also has my favorite overworld warp system in the series.
1. Rocky Mountain Trophy Hunter 3 (PC)
My favorite game from a genre that nowadays is almost non-existent, and in many cases where it does exist it's completely misconstrued. Also probably the first game I ever played.
Some honorable mentions:
Tom Clancy's Splinter Cell: Chaos Theory (PS3)
Carnivores 2 (PC)
Eternal Darkness: Sanity's Requiem (GCN)
Tom Clancy's Rainbow Six 3 (GCN)
Call of Juarez: Bound in Blood (PS3)
Uncharted 2: Among Thieves (PS3)
Super Mario Bros. 3 (NES)
Mario Kart DS (DS)