Ran into this from ajaxian, might serve as a decent reference or model for the new HTML5 theme:
It's an out-of-the-box website template that utilizes a lot of well-established and still-establishing techniques of handling HTML5 for multiple browsers.
All of the source is available on that page for your perusal. And as the website claims, if you don't like it, the boilerplate is delete-key friendly.
Enjoy!