Win+Down Restore / Minimize
Win+Left Snap to left (pressing again will jump over to the next monitor)
Win+Right Snap to right
Win+Shift+Left Jump to monitor on the left
Win+Shift+Right Jump to monior on the right
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+Space Peek at the desktop
Win+G Bring gadgets to the top of the z-order
Win+P External display options
Win+X Mobility Center (same as Vista, but handy)
Win + # 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.
Alt+P Toggle the 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 (with Restore / Minimize / Move / etc).
(Note that the normal way to access this menu is to right-click on the window thumbnail)
Shift+Right-click on a grouped icon will show Restore All / Minimize All / Close All, etc.
Ctrl + Click on a grouped icon will cycle between the windows (or tabs) in the group.
Windows 7 Beta hotkey cheat sheet