HTML5 not ready for prime time, says W3: http://bit.ly/blTwrj.
The World Wide Web Consortium, the body that regulates and publishes the specifications of the HTML standard, is warning web content producers that the HTML5 is “not yet ready for production” and that the W3C will likely make further significant changes to the specification to increase interoperability. Philippe Le Hegaret, interaction domain leader responsible for the HTML and SVG spec, added that they expect it to be feature-complete in mid-2011.
This hasn’t stopped a lot of people already making the move to HTML5 where it makes sense as a Flash (or Silverlight) replacement.
In the meantime where there’s a showcase of  “15 Excellent HTML5 Techniques and demonstrations“