Tetris Attack, Mario 3, Donkey Kong Country 2, Paper Mario 2, Tales of Symphonia, Advance Wars: Dual Strike, Chronno Trigger, Advance Wars: Days of Ruin, and Super Smash Brothers: Melee (NOT Brawl, even though I played it lots of times) are games that I think are really good.
They are in no real order, but Advance Wars: DS, Tetris Attack, Paper Mario 2, Chrono Trigger, and Donkey Kong Country 2 are basically tied for the award for my favorite game.