In this tutorial we will see another icon theme for Ubuntu called Meliae SVG, you can find it here. Here is the set of icons used by this icon theme:
To install and enable the Meliae SVG icon theme under Ubuntu 11.10/12.04, run these commands from the terminal:
wget -O Meliae.zip http://goo.gl/lji5S && unzip Meliae.zip
sudo tar -xzvf MeliaeSVG.tar.gz -C /usr/share/icons/
gsettings set org.gnome.desktop.interface icon-theme 'MeliaeSVG'
Here is a screenshot of this icon theme under Ubuntu 11.10:
You can find here more icon themes.