I just wanted to let you know about site that I've created called html5gallery
It is intended to showcase sites that html5 for markup and has twin aims to educate developers on how to use html5 and to help persuade browsers developers that they should implement better support for html5 as people are using it now.
Take a look at let me know what you think. Also if you know of any sites built using html5 that I've missed please let me know.
You can also follow @html5gallery on twitter for updates when new sites are added.