I think that using the new HTML doctype is worth going for. Using new elements like <section>, <header>, <nav>, and <footer> instead of <div id="section1">, <div id="header1">, <div id="nav"> and <div id="footer"> is worth it too.
In IE (as far back as 6) you can use the document.createElement("someElement"); JS instruction to make sure that you can style the elements with CSS. The other modern browsers will let you style the new elements the same way you can adjust <div> with CSS already. Sure, these new elements are meaningless right now, but so are <div>s. Future browsers will be able to recognize the semantic meaning behind the new elements while <div> will remain meaningless.
The other new elements? Well, save that for your personal website experiments until you are convinced you know how you can add value to a client's site using them.
...The thing is, I think IE 6 will still be around (let alone other browsers that don't yet support the new elements) by the time HTML 5 is a recommendation. So you should at least get some practice with working around and with HTML 5 and incomplete browser support now, so you don't have to later (when a client
demands an HTML 5 website).
[EDIT] (I do this edit thing lots)
http://stackoverflow.com/questions/186264/is-it-time-to-start-using-html5 describes the current situation from another perspective. So, despite my idea of using the new semantic elements, perhaps you should wait to see how UA's implement the new elements. Canvas is ok, though.