Advance Wars: Dual Strike
Animal Crossing: Wild World
Meteos
Mario Kart DS
Castlevania: Dawn of Sorrow
Super Mario 64 DS
Mario and Luigi: Partners in Time
Kirby: Canvas Curse
Metroid Prime Pinball
Phoenix Wright
To keep an eye on:
Super Princess Peach (February 27th) - Looks like it has potential to be as good as any other Mario game. At any rate, it should have more replayability than Kirby.
Tetris DS (March 20th) - It's Tetris. Besides that, it looks kind of like the upper screen will play sequences in NES games depending on how well you score, which seems interesting.
Metroid Prime Hunters (March 20th) - Could be a decent FPS. I haven't heard enough about the single-player mode yet.
Guilty Gear: Dust Strikers ("early Spring") - The Guilty Gear engine should theoretically work well with the DS' vertical orientation.