My favorite game of all will be none other than Super Mario Sunshine. It was a game I grew up with back in 2002, and I still have my copy of the game.
At second would be Sonic Heroes, holding a fond memory of completing the game AND on Super Hard mode. I'd do it again if it didn't drive me crazy.
Also, Animal Crossing: New Leaf has become on my top favorite list, for being dedicated to it since last year.
Other honorable top favorites:
Zelda: Minish Cap
Pokemon HGSS
Donkey Kong 64 (101% percented it, too!)
No More Heroes
At second would be Sonic Heroes, holding a fond memory of completing the game AND on Super Hard mode. I'd do it again if it didn't drive me crazy.
Also, Animal Crossing: New Leaf has become on my top favorite list, for being dedicated to it since last year.
Other honorable top favorites:
Zelda: Minish Cap
Pokemon HGSS
Donkey Kong 64 (101% percented it, too!)
No More Heroes