The entire spec is pretty awesome, I enjoy all of these new features and it really does give us developers a lot more to work with. Unfortunately most of these features aren't supported by most browsers, but if you need to Do note that localstorage and most of the "features" are actually JavaScript, as HTML5 is just the whole package. If you need to use HTML5 elements (which isn't something I'd waste my time converting for), make sure to use html5shiv, or even better, Modernizr.

You might be interested in the Adobe Expressive Web page