"HTML 5 Up and Running" is the print version of the book posted at diveintohtml5.org. It covers the new features in HTML 5 along with which browsers support what (and how to do feature detection.) It's a concise book at 205 pages and sells for just under $20 dollars.
At the moment, the content is current. This may or may not change depending on how faithfully the browsers implement the spec.
I bought the book for two reasons:
1) I read the HTML version in it's entirety and wanted to support the author.
2) I like reading books away from the computer and scribbling it them.
Before buying the book, check out the website and see what you think for yourself. For me, it was buy.