Foopanel is a powerful plugin-based themable desktop panel that enables you to have all that you want just one-click-far. Foopanel is similar in concepts to the Gnome and Xfce panels, but differs from these because it is written in Python, so it is very easy to write plugins, and because its appearence can easily be customized, by using a theme of those available or by writing a custom one.
Foopanel is quite independent from the desktop-environment/window-manager in combination with which it will be used, though some plugins require some Gnome parts.
Currently Foopanel comes with two plugins bundled, a new-concept menu and a date-time clock. More plugins are available in the SVN version, although not all of them are working.
NOTICE: since Foopanel development stopped, you can now use BarPanel, which is a continuation of the work by M. Kero.