I don't own very many anymore, since I sold most of them before I traded my DS Lite to a certain member on this forum (Still kind of angry about that, since I have to use my brother's DS Phat, and it has this annoying speck under the screen).
I still have Guitar Hero: On Tour Decades (My favorite in the series) with the grip, Pokemon Diamond (With over 200 hours played), and Animal Crossing: Wild World (I remember getting it for Christmas the year it came out).
I pre-ordered Pokemon SoulSilver yesterday (I still have $12 or so left to pay off), so when it's released, I'll have that as well.
This is a little off-topic, but I also got the Pikachu-colored Pichu yesterday at my local GameStop. The color is somewhat noticeably different, but I didn't get it for that, so it doesn't matter to me (It's supposedly for the spiky-ear Pichu in Ilex Forest on HG/SS or something like that).