The Expressive Web is Adobe’s showcase of HTML5 and CSS3′s features and functionality. They offer simple statistics per feature and I think their reference to modernizr is a great one.
That, and the execution is great. The page transitions, whilst keeping a proper permanent link structure are nice. The page load from a permanent link is great. And the performance is nice, even whilst I’m running it in a large browser window on my two year old onboard video card.