François Vogelweith is the author of zgegblog, a site that maintains a collection of great GNOME themes. Balanzan (translated: Balance) is one of its most popular creations, a very comprehensive theme based on Ubuntu Jaunty Jackalope, which contains a wallpaper, logon theme, Emerald theme, controls and icons.
On his website there are the nine themes so far, all with very exotic names, usually some variation in colors and shapes. Most themes even come with a AWN themes.
For helping Ubuntu users, these themes are also available in .DEB packages and there is also a Launchpad repository that you can add so that you can install any of themes (installation command between the brackets after you have added the Ubuntu repository, see below):