*New Super Mario Bros.--I've always liked the idea of a 3D SMB game. The Giant Mushroom is great fun!
*Super Mario 64 DS--It's a puzzle/collecting things game. Think of Donkey Kong 64, but with Mario.
*Nintendogs--Gets old quick, but pretty cute!
*Mario Kart DS--You play most of the classic Nintendo Mario characters, and choose from different machines and race on cool tracks and set traps! :P
All the good ones I have played (Poke'mon Trozei is freaky!
)
There's a rumor of a Silent Hill DS game, but it sounds like an awkward design.