Ben, in terms of hardware, I totally agree with you. However, the games for that have recently been released for the DS have achieved critical and commercial success. Mario Kart is a great seller, as well as Animal Crossing. I never played either of those titles, but I am a big Mario Kart fan and supposedly Mario Kart DS is the best game ever in the series. Plus it's online, which makes it that much better.
I mentioned the huge sales of games in Japan, the interesting thing is that a lot of those sales are going to adults. This is because of the Brain Training series of games that have been released there. There are a bunch of different titles in the series, and they're continually coming out with new ones there. And they're selling like hotcakes. Those games will get released in the US before summer of this year, so it'll be very interesting to see how that affects the sales of the DS especially in regards to the demographics it appeals to. The touch screen really lends itself well to cross-word puzzles, brain teasers etc, and with the new Sudoku craze, having it on the go is pretty compelling.