I'm trying to think of something, but I'm coming up blank. Most decent Japanese DS games either have been localised, or will be soon. If rhythm action's your thing you could go for the two Ouendans and Taiko no Tatsujin I suppose. And if you're in the US, get the European version of Tingle's Rosy Rupeeland (or even the Japanese if you speak it), since I suppose that counts as an import from your perspective/