I use this quite a lot
Alt + space bar = Minimise/Maximise menu
Ctrl + C and Ctrl + V from the clipboard is vital to me when editing text and also in photoshop.
Windows logo key + E = Open Windows Explorer
Windows logo key + M = Minimise all open windows
Another useful keyboard command is the "Print Scrn SysRq" button which will do a screen grab to clipboard... then in photoshop select new and then Ctrl + V to paste it. If you don't want the whole screen grabbed you can use Alt + Print Scrn to grab the window currently open.
And one of my all time favourites is
F11. Just hit F11 now.
