CodersMidnightTheme is a very dark GTK theme based on Cobra-Brown.
Just extract the archive to $HOME/.themes/. Then select it in Configuration -> User Interface -> Theme (in Xfce4).
· GTK 2.x
· GNOME 2.x
What's New in This Release:
· Added metacity theme
· Fix: The theme appeares in the gnome appearance panel, now.