It looks pretty nice but the use of background gradients is inconsistent. The buttons with a background image have no gradient but the other buttons do.
Lots of details here and some catches to look out for (mostly browser support).
Warning: Multiple backgrounds can lead to LOTS of waste in the CSS (defining gradients over and over) if you aren’t using sprites for those icons (and setting all of them at once).
Nope, I don't think there are any (the CSS3 workarounds can be tricky with custom padding/margin). Google consistently uses nested elements and I think for the next few years that's the only solution that's going to work well cross-browser.