Windows 7 has some useful shortcuts which are absent in Windows Vista or Windows XP. Windows 7 Shortcuts is a freeware that enables some of the best windows 7 shortcuts for Windows Vista and XP.
Win+Left/Right arrows: Dock the window to each side of the monitor
Win+Up arrow: Maximize the active window
Win+Down arrow: Minimize the window/Restore the window if it’s maximized
Win+Space: Note from the developer: AHK won’t allow multiple windows to be made transparent easily. Therefore, I’ve changed it to make the active window transparent until it is released.
Via Lifehacker, Download Windows 7 Shortcuts (direct link)