10. Minecraft. While I do enjoy the game and would be content to play it for awhile, it just gets boring and tedious after awhile.
9. Scribblenauts Unlimited. I love giving random things some incurable disease and then unleashing it on the world.
8. Battleblock Theater. Cute little game and interesting dialogue.
7. Vindictus
6. MarioKart 64. Who doesn't like MarioKart?
5. The Fallout Series. I enjoyed playing all of them, even if the first two glitched out within seconds of me playing
4. Skyrim
3. Oblivion
2. The first three Spyro games. The first game I ever played was Spyro the Dragon. The second was it's sequel Ripto's Rage. The third was probably Zelda something or other.
1. Morrowind

Honorable Mentions: Left4Dead 2, Dead Rising 1 and 2, Legend of Zelda: Majora's Mask.