Changing Your Icon Theme
I’m not a fan of the Icon themes that come with Oneiric. Here’s how I changed them.
Begin by installing gnome-tweak-tool:
sudo apt-get install gnome-tweak-tool
After installing, launch ‘Advanced Settings’ which is the name gnome-tweak-tool goes by in menu based launchers (Dash, Cardapio, etc.)
Select ‘Icon theme’ and change to one of the items in the dropdown list. I selected Oxygen.