I've upgraded from 11.10 to 12.04. I was using Gnome-Shell in 11.10 and still am on the current install.
I've noticed an inconsistency between the themes of applications - some appear black whilst others appear white, like this:
Nautilus is appearing in the white theme, whilst Movie Player is in black.
Adwaita is the theme that's selected for the GTK+ and Window themes.