Windows Aero features 1

Windows + Spacebar 
Make all open windows transparent to view gadgets and icons on desktop.

Windows + D 
Show or hide the desktop.

Windows + Home
Minimize all but selected window. Reverse by clicking the key combination again.

Windows + left arrow OR Windows + right arrow 
Dock selected window to the left or right half of your screen.

Windows + up arrow OR Windows + down arrow
Maximized and restores the selected window.

Windows + SHIFT + up arrow OR Windows + SHIFT + down arrow
Maximizes and restores selected window in vertical dimension only.

Windows + Tab
Launch 3D representation of open windows and click Tab key again to flip through them.

Alt + Ctrl + Tag + left/right/up/down arrow
Flip window.

Alt + Tab
Cycle through open windows.

Windows + T OR Windows + SHIFT + T
Move focus to front or back of taskbar. Press T again while holding the Windows key to cycle through items in the taskbar from left to right or, with SHIFT button held too, from right to left.

Windows + B
Puts focus on the ‘show hidden icons’ button on the system tray.

Windows + 1 THROUGH Windows + 9
Launch first through ninth icon on taskbar, including items pinned to taskbar.

Windows + SHIFT + 1 THROUGH Windows + SHIFT + 9
Starts new instance of respective taskbar icon.

Windows + Ctrl + 1 THROUGH Windows + Ctrl + 9
Cycles through multiple instances of the respective icon.

Windows + Alt + 1 THROUGH Windows + Alt + 9
Opens jump list for respective icon.