Here's how you can install the Ursa icon theme in Ubuntu 14.04. This icon set is still in beta, but it looks great in Ubuntu. See the screenshot below for a sample of what the icons look like.
1. Open a terminal window.
2. Type in the following commands then hit Enter after each:
sudo add-apt-repository ppa:noobslab/icons
sudo apt-get update
sudo apt-get install ursa-icons
Source: Noobs Lab
Additional resources for Ursa Icons
Additional Ubuntu resources