This is a great idea. The use of AJAX to keep everything on one page is kinda like how MSNBC has made its article pages require as little clicking as possible. Except less maximalist. For what it's worth, I put it on my blog and referred to it as "A pretty badass HTML5 take on the Pandora model."

I'm going to try this on the iphone. I like how the design is clearly made with that in mind, while still being perfectly usable on the desktop.