
improving apperance
If you are looking to improve the desktop appearance and give it a cool factor, look for compiz-settings-manager in the software center or synaptics package manager. This will allow you to enable things like the cube desktop, window animations, wobbly windows, etc.
Cube desktop is by far the most useful eye candy I have ever used. Works much better than the standard desktop pager when trying to navigate through applications with a lot of screen updates. I use it with my recording software to navigate between my mixing, editing and mastering programs.