Win+Up = Maximize
Win+Left = Snap to left
Win+Right = Snap to right
Win+Shift+Left = Jump to left monitor
Win+Shift+Right = Jump to right monitor
Win+Home = Minimize / Restore all other windows
Win+T = Focus the first taskbar entry
Pressing again will cycle through them, you can can arrow around.
Win+Shift+T = cycles backwards.
Win+Space = Peek at the desktop
Win+G = Bring gadgets to the top of the Z-order
Win+P = External display options (mirror, extend desktop, etc)
Win+X = Mobility Center (same as Vista, but still handy!)
(# = a number key) Launches a new instance of the application in the Nth slot on the taskbar.
Example: Win+1 launches first pinned app, Win+2 launches second, etc.
Win + +
Win + -
(plus or minus key) Zoom in or out.
Alt+P = Show/hide Preview Pane
Shift + Click on icon = Open a new instance
Middle click on icon = Open a new instance
Ctrl + Shift + Click on icon = Open a new instance with Admin privileges
Shift + Right-click on icon = Show window menu (Restore / Minimize / Move / etc)
Note: Normally you can just right-click on the window thumbnail to get this menu
Shift + Right-click on grouped icon = Menu with Restore All / Minimize All / Close All, etc.
Ctrl + Click on grouped icon = Cycle between the windows (or tabs) in the group
taken from http://brandonlive.com/