E16 is the best.
Just installed the Enlightenment e16 desktop on Linux Mint 7, it takes me back to using Debian 3.0 and enjoying this awesome graphical desktop. Absolutely cool. The Enlightenment E16 window manager has been around for a long time and always delivers a quality desktop experience. There is a page here that provides information about installing Enlightenment E16 on Ubuntu Hardy: https://help.ubuntu.com/community/Enlightenment.
To install Enlightenment E16 just run this command.
sudo apt-get install e16