I want to use Ubuntu but don't have a computer to run it on other than the main one. Therefore I did the next best thing I customized the pi and I will gladly customize it in this instructable.
Step 1: Changing the Theme
first things first, before you change the entire setup to match Ubuntu. Right-click the screen and go to ObConf. this is the openbox configuration manager. After that choose the Onyx-Citrus theme and hit close.
Step 2: Desktop Preferences
Go to the terminal and type in:
pcmanfm --desktop-pref. Next hit enter and hit wallpaper and browse for any previously downloaded Ubuntu wallpaper. I chose 14.04 but you can choose whichever you want (make sure it is high res or it will turn out pixelated).
After that choose wallpaper mode and choose whichever one fits the screen the best, I chose "stretch to fill the entire screen." Hit close and go to the next step.
Step 3: Moving the Panel (optional)
Last step for those who want thier panel on top...
Right-click the panel and go to the option that says "Panel settings" and click it. Go to the Position section of the geometry tab and click top.
Finally go to the Advanced tab and click the "minimize panel when not in use" and change it to four pixels on the "size when minimized" option. Finally hit close and enjoy your changes.