Update: Unfortunately I'm no longer able to maintain and/or update Starkers HTML5 although you can still get a copy from GitHub and use it in its current state.
Like so many others I found Elliot's theme invaluable, and so about 7 months ago I decided to create an HTML5 version that others would be able to use.
With the introduction of Wordpress 3.0 I'm pleased to unveil the new version of Starkers HTML5, just like the previous version this one has been based on Elliot's Starkers, which in turn was based on the new default theme known as Twenty Ten.
So what's new?
Thanks to Wordpress 3.0 theme developers now have new APIs that allow them to easily implement custom backgrounds, headers, shortlinks, menus, post types, and taxonomies.
The Twenty Ten theme shows off all of these new features, whereas Starkers leaves the functionality but strips back the styling.
For a more comprehensive look at everything that has improved in Wordpress 3.0 you can check out the 3.0 Codex page.
Although Starkers HTML5 is a great starting point for any WordPress theme development I highly recommend you take the time to check out and dig through Paul Irish and Divya Manian's HTML5 Boilerplate.