I'm super pumped for it...almost as much as I am for Rhythm Thief and the Emperor's Treasure.
But I'm a bad example, because I think rhythm games and the DS are chocolate and peanut butter (as in they are perfect for each other).
I've got Elite Beat Agents, Ouendan 1 and 2, and Band Bros., Band Bros. DX, AND the Band Bros. Request Selection for my original DS. (Note: If you've never heard of these, Elite Beat Agents was the only one released in the U.S., and Band Bros. was Jam with the Band in Europe. I have the original Japanese ones.)
And Theatrhythm comes out July 3, Rhythm Thief July 10, and then Kingdom Hearts: Dream Drop Distance is July 31. Better start saving now, it seems.