What is HTML 5? I hear you ask. Well apparently it’s mostly HTML 4 with some extra tags and attributes.
For the structural elements of HTML 5, we have the following:
* section: A part or chapter in a book, a section in a chapter, or essentially anything that has its own heading in HTML 4
* header: The page header shown on the page; not the same as the head element
* footer: The page footer where the fine print goes; the signature in an e-mail message
* nav: A collection of links to other pages
* article: An independent entry in a blog, magazine, compendium, and so forth
Which is lifted straight from this IBM Developerworks page. There is a great deal more on that page that I am not going to detail here including examples, so I suggest everyone read though it.
HTML 5 isn’t hard, it is compatible with HTML 4 and degrades nicely. Near as I can tell it seems designed to bring web design more in line with the conventions used in GUI application design (Progress bars for example) in addition to adding different methods of embedding video and audio. It would be a surprise if the changes didn’t find their way into the next generation of xHTML as well.