|The Gorgeous Faenza....|
*. Monochrome icon set - For dark and light panels + menus.
*. Squared icon set - Starting with all the major GNU Linux apps that comes with Ubuntu + some other popular third-party app icons ... this suit includes an impressive amount of icons that helps you to completely "Faenza-nize" :) your Ubuntu Desktop.
You can install it using two main methods. As usual, you can visit the developer's page and download the icon set and follow the instructions or, can use the Terminal with a PPA channel for installing it which is the best/easiest in my opinion.
So, if you're interested in the PPA method, then open your Terminal and issue the below command.
sudo apt-add-repository ppa:tiheum/equinox
sudo apt-get update
sudo apt-get install faenza-icon-theme
*. This should work for Ubuntu 10.04, 10.10 and 11.04 versions.