Chopin's Dream
Just took the Eternal Sonata ('Trusty Bell: Chopin's Dream' in the Japanese, IIRC) for a spin and holy cats. First game I've played on the 360 that's made me want to run out and buy one (which I um, will be shortly). Viva Pinata is fun and all, but I am so so so very impressed with the demo - the battle system is great and it is gorgeous, but not in a Final Fantasy kind of way.