These are probably the most useless ones here yet, but (<windows key> + e) brings up My Computer (at least in windows XP), while (<windows key> + r) brings up the run bar...again for those who like the keyboard better then the mouse, this is a better way of running programs then start programs or start run .
Here are more....
Alt+Shift+Tab :Switch backwards between open applications
F5 :Refresh Contents
F3 :Start find from desktop
F2 :Renames selected Icon
Ctrl+Win+F : Find Computer
Shift + F10 does the right-click option of the mouse
For Example,using the TAB button you can highlight the My Compter icon.pressing ENTER will open it.but how will you Explore its properties or do a right-click without the mouse?