From the Google I/O keynote: HTML5 support will be more or less complete on all "modern" browsers, says Google. That slight dig by Google is intended, I'm sure.
I don't understand why people being too lazy to update their browsers is such a major problem. Why don't the browsers just update themselves? 100% of Internet users are on the Internet, so why can't the browser just update itself in the background, leaving these people oblivious to the fact that an update has even happened? Everybody wins.