Setting the 'Show Desktop' keyboard shortcut in Ubuntu

Having just moved from a Windows environment to Linux, I have been trying to find my way around Ubuntu 9. Everytime I have something that I want to do in the OS, I have used the Windows way of doing it, without any success :p

For those of you trying to set up your Linux OS to 'Show Desktop' when the Windows + D key is pressed, this is what I found out on how to do it:
1. Go to System -> Preferences -> Keyboard Shortcuts

2. By default, Ubuntu responds to Ctrl-Alt-D to 'Show Desktop'. You can change this to Windows + D by firstly pressing the Windows key (or called Super in Linux which I havent quite figured out why), then simultaneously clicking on the keyboard shortcut for the "Hide all normal windows and set focus to the desktop background" option and hitting the 'D' key.

This will map a Windows-D keypress to 'Show Desktop'!