Zoo Keeper works really good with the stylus, as well. However, oddly enough, don't underestimate the minigames in Mario DS. They have some really cool ones in there, all using the stylus. Some of the minigames are full puzzlers. That along with Wario Touched has some of the neatest uses for the stylus. Some of them because you create stuff with the stylus (real time) and play with them. Like generating platforms, on the fly, or mazes or tracks for which things can navigate.
In a way, I have a feeling Yoshi's new game will utilize that aspect. An aspect where you not only play the level, but you have a hand in crafting or editing a level, as a part of the gameplay. Of course, I got the stylus for some unique stylus aspects, and also the japanese game aspects, of which it's still getting unique stuff. (The high japanese sales also seem to make me think we'll see some unique stuff before the DS is over). And for me, certain quirky stuff like Jump Superstars, have my attention. I'll probably get a PSP, eventually, but I've learned the hard way never to quickly jump on a Sony creation . I know I want to wait for 2nd gen (after the kinks are worked out), so I have a little more lone DS time, than some.