Card-battling games seem like a natural for the DS-- the second screen is especially well-suited for managing cards while the game is in play. But we haven't gotten that many card games-- in fact, SNK vs. Capcom Card Fighters DS is the only one we can think of, and that one's not even out yet.
Hudson's Elemental Monster is a turn-based card-battling game that uses some pretty great 2D sprites. Between battles, the game has an RPG-style story mode, which also uses a lot of hand-drawn 2D. We're actually surprised to see a DS game coming out that has this much non-polygonal art (some backgrounds are 3D, but that's fine!) How about a US release, Hudson?