Users should have more say in the Look and Feel of Ubuntu. http://brainstorm.ubuntu.com/idea/24918
Directly including user made themes would promote the idea that people can contribute.
Please include the highest rated theme on gnome-look.org in each new Ubuntu Release or provide a similar way for users to vote on some included themes.
http://gnome-look.org/index.php?xsortmode=high&page=0&xcontentmode=100
ps. the current top is pretty nice http://gnome-look.org/content/show.php/Equinox+GTK+Engine?content=121881