Sonic Rush Adventure
So far this is shaping up to be better than the original Sonic Rush, which I absolutely loved. The 3d world is really well blended into the 2d gameplay which is something that I don't think I've seen done quite this well. Every thing about this game just screams the classic gameplay many of us grew up on in the Genesis years.
My only complaint is the lame Sonic story and dialog we have all gotten used to in the past decade or so. If you like platformers, Sonic, or own a DS you should go buy this!