Window 7 Shortcuts:

Taskbar Modifiers
Shift+ClickOpen a new instance of the program
Ctrl+ClickCycle between windows in a group
Middle ClickOpen a new instance of the program
Ctrl+Shift+ClickOpen a new instance of the program as Administrator
Shift+Right-ClickShow window menu
Managing Windows
Alt+F4Close the active window
Alt+TabSwitch to previous active window
Alt+EscCycle through all open windows
Win+TabFlip 3D [more info]
Ctrl+Win+TabPersistent Flip 3D
Win+TCycle through applications on taskbar (showing its live preview)
Win+MMinimize all open windows
Win+Shift+MUndo all window minimization
Win+DToggle showing the desktop
Win+↑Maximize the current window
Win+↓If the current window is maximized, restore it; if the current window is restored, minimize it
Win+←Dock the current window to the left half of the screen
*If it is already docked left, it is moved to the right half of the screen
*If it is already docked right, it is restored to its original size
Win+→Dock the current window to the right half of the screen
*If it is already docked right, it is moved to the left half of the screen
*If it is already docked left, it is restored to its original size
Win+Shift+←Move current window to the left monitor (with dual monitors)
Win+Shift+→Move current window to the right monitor (with dual monitors)
Win+HomeMinimize all but the current window
Win+SpacePeek at the desktop
Win+[Plus sign]Zoom in
Win+[Minus sign]Zoom out
Starting Programs
Win+1Open the first program on your Quick Launch bar
Win+2Open the second program on your Quick Launch bar
Win+nOpen the nth program on your Quick Launch bar
Win+UOpen the ease of access center
Win+FOpen the search window
Win+XOpen the Mobility Center
Win+EOpen Explorer
Win+ROpen the Run window [more info]
Win+BMove focus to notification tray (the right-most portion of the taskbar)
Win+POpen the projection menu (generally used for laptops connected to projectors)
Win+PauseOpen the System Properties portion from the Control Panel
Ctrl+Shift+EscOpen Windows Task Manager
Logging In And Out
While the below shortcuts seem unwieldy because of their length, they're quite easy to remember once you try them out a few times.
Win, →, EnterShutdown
Win, →, →, RRestart
Win, →, →, SSleep
Win, →, →, WSwitch Users
Win+LLocks computer
Viewing Folders With Explorer
Alt+←Go back
Alt+→Go forward
Alt+↑Go up a directory
Alt+DMove focus to address bar
Alt+D, TabMove focus to search bar
Alt+EnterOpen the Properties window of the current selection
Ctrl+MousewheelChange the view type (extra large, small, list view, detail, etc.)
Alt+PShow/hide the preview pane