I just updated to the latest nightly build of Firefox 3 beta (Minefield) and you can see the beginnings of the new theme for Vista coming up. A couple of pictures…
Notice the integrated Back and Forward buttons (Vista like). It actually looks more like the UI elements of early Windows Longhorn builds.
Also notice that Home is no longer a button in the standard toolbar, but has instead been moved to the Bookmarks toolbar. I don’t like this since I usually turn off the Bookmarks toolbar so that I have more space for my web browsing. But it’s an easy fix to move the Home button back to the standard tool bar — right click on the standard toolbar->Customize->drag and drop the Home button from the Bookmarks toolbar to the standard toolbar.
The ‘About’ dialog just for your reference.