Right now, I have:
Super Mario 64 DS - Not very good, especially the stylus substituting for the analog. It's just a slightly touched-up version of Super Mario 64. Though some of the minigames are mildly entertaining.
WarioWare: Touched - Makes good use of the touchscreen. Fast paced and fun for a while, but microgames get boring after playing them awhile. Has no real story. Wario steals a DS and decides to make money off of it.
Trace Memory - Haven't played it enough to judge it, but so far it's reminding me of old Sierra games with the point-and-click interface(Space Quest, King's Quest), but with a top-down view.
Trauma Center - Very Nice. I don't think this game would've made the cut without the DS. The use of the touchscreen is the best I've seen on the DS thus far. It's difficult, but gives a great feeling of accomplishment when you complete an operation. Have no doubt, some of the operations WILL make your hand shake. Though you don't see most of the patients, some of the few you do will make you want to save them. Some of the anime scenes can be a bit cheesy though. Such as Derek, the main character, sticking out his hand and saying "Let's begin the operation!" and the Healing Touch ability is especially cheesy when you're fighting a certain virus near the end of the game. It is also annoying that their is no voice acting because often times you will need to look at the top screen to read information. The game usually pauses when new information comes up, but not always. This can lead to failed operations pretty easily. Anyway, I think I devoted too much space in my post to this game, but it really a unique game, and I would highly recommend it.
