Windows logo key+Up Arrow Maximize the window.
Windows logo key+Down Arrow Minimize the window.
Windows logo key+Left Arrow Window to the left side of the screen.
Windows logo key+Right Arrow Window to the right side of the screen.
Windows logo key+D Display the desktop. Hitting it again, restores the windows that were displayed.s
Windows logo key+Spacebar Preview the desktop. When  you let up on the Windows key, the original windows return
Windows logo key+M Minimize all windows. Letting up does not return them to their original size
Windows logo key+Shift+M Restore minimized windows to their original size
Windows logo key+Shift+Left Arrow or Right Arrow Moves the window to another monitor
Windows logo key+Home Minimizes all windows except the active one.
Taskbar Related Shortcuts
Windows logo key+T Cycles through the programs that are pinned on the taskbar
Windows logo key +number Starts the program pinned on the taskbar related to it's position. For example logo key+1 would start the first program pinned to the taskbar
Ctrl+Windows logo key+number Changes to the last active windows for that numbered program pinned to the taskbar
Alt+Windows logo key+number Opens up the jump list for that program pinned to the taskbar
Ctrl+Shift+Click on a taskbar button Starts a program on the taskbar as Administrator
Flip 3D
Windows logo key+Tab Cycles through the running programs
Ctrl+Windows logo key  +Tab Cycles through the running programs letting you use the arrow keys. I find there is a bit more control using this method.
Misc
Windows logo key+E Opens up My Computer
Windows logo key+R Opens up the Run box
Windows logo key+P Choose the monitor configuration. For example, dual, single or projector. This can be very useful when having a laptop with a projector attached.
Alt-P Shows the Graphic Preview Pane. This can be useful when you want to display a preview of photos in a particular folder. It is much larger than viewing thumbnails and can be faster than needing to start a 3rd party program.