The quickest way to maximize your current program when using windows. (without using your mouse). Microsoft chose to not include a two-key shortcut for this basic, oft-used function, so this is the next best thing.
Alt space x.
Alt then space then x.
Learn it, live it, love it.
Actually, it doesn't minimize all windows, it shows the desktop. There is a slight difference. When you maximize any window, all your former maximized/restored windows will open again. Window Key + M is actually the minimize all shortcut, however if an application has a dialog open, it will not minimize it.
windows key + D shows the desktop, Windows key + M minimizes all windows that don't have open dialog boxes.