Here is a nice opportunity to make your desktop icons more colourful with color icon theme ,Humanity Colors. This is nothing  but a modified version of icon humanity for gnome desktop environment. Download this nice icon theme from GNOME-Look.org. After downloading unpack , the file and the folder on to System => Preferences => Appearance. Hurray you are done. More details can be found at http://gnome-look.org/content/show.php/Any+Color+You+Like?content=102435 .