Well, that would be a tie between Secret of Mana and The Legend of Zelda: Majora's Mask. I enjoy games mainly because of the associations they bring me. I actually didn't play LoZ: MM before it was released for GameCube - never had a N64 - but I instantly loved it because I got the "Zelda feeling" from it.
I also like the Fire Emblem series, the Worms games, the other Zelda games, the Super Smash Bros. series, and the StarWing/StarFox series. I also enjoy GTA: San Andreas from time to time.
Lately, I've played minesweeper a lot, but I'm too bored by it now.