GnomishDark is a clean dark theme for GTK3, based on the Adwaita engine, plus a matching GNOME-Shell theme.
It also contains a GTK2 theme, that depends on the latest Murrine and Pixmap engines.
*** Current Dependencies ***
GTK3 = 3.8.X
GNOME3 = 3.8.X
gnome-themes-standard = 3.8.X
gnome-shell = 3.8.X (for GNOME-Shell)
gtk2-engines-murrine >= 0.98.1.1 (for GTK2)
gtk2-engines-pixbuf >= 2.24.10 (for GTK2)
Metacity >= 2.34 (for GTK2)
*** Notes ***
1) If you still have gtk-3.6.0, download the older version from here: [link]
2) Ubuntu users could disable "overlay-scrollbar" if they want to have the original scrollbars of the theme. See [link]
3) Don't forget to take a look at the file "README" in the theme folder. It contains useful tips for LibreOffice, Firefox, Epiphany, etc.
4) The panel font is Bitstream Charter, provided by xfonts-scalable in Debian based systems and by xorg-x11-fonts-Type1 in Fedora, but it's not necessary.
5) Light monochromic icons go well with this theme. I've made the gray version of nouveGnome [link]
Jul 11 2013
Updated for Gnome-3.8 and GTK+-3.8.
Removed the Cinnamon theme (sadly I couldn't maintain it with so much of backward incompatibility in Gnome).