I don't know where you got your stats from, but Firefox and Opera support HTML5 and (most of) CSS3. IE is still the only browser lagging, but IE9 is supposed to catch up. However IE support for the canvas tag is still questionable.
Correction, Firefox and Webkit have their own implementation of parts of the CSS3 standard - unfinalised.
IE isn't lagging, it is waiting until these standards are near enough complete for reccomendation before it implements them in the software.