Now here is a pretty hot icon set, its more complete than the others I have shared...
The elementary icon set focuses on simplicity and clarity while being realistic. They are inspired by many different popular icon sets, such as Tango, Crystal, Developers Icons, Elements Icon Suite, etc
wget http://ubuntu-debs.googlecode.com/files/Elementary_1.7.tar.gz ; tar zxvf Elementary_1.7.tar.gz ; mv Elementary_1.7 ~/.icons
More info @ gnome-look.org
Right Click Desktop->Change Backround->Theme->Customize->Icons->Select Elementary->Close