Well, I mean, the sytems do actualy have a differense this time...
Like some people ACTUALY like being "interactive" with their games, via the touch screen + the mic. That's just one reason to buy the DS with a game that is made by a good company and uses those things and the Nintendo WiFi, plus a Hard Drive which stores your songs and videos and such, you've got yourself a pretty sweet deal...
So it's not just the games you like, it would be other things too...or if you are a Nintendo fanboy.