Here is another icon theme for Ubuntu called Vibrant which is a set of icons that will make your Desktop look better. In this page we will help you install this icon theme under Ubuntu 11.10/12.04.
Vibrant Icon Theme Installation
Just run these commands from the terminal:
wget -O vibrant-9.7.tar.bz2 http://goo.gl/UOMDK
sudo tar jxvf vibrant-9.7.tar.bz2 -C /usr/share/icons/
gsettings set org.gnome.desktop.interface icon-theme 'vibrant'
Here is how this icon theme looks under Ubuntu Oneiric:
For more icon themes for Ubuntu, check this list.