At 1.6 pounds, the Vaio X from Sony is the lightest notebook out there. The Vaio X is not a high-performance machine given it uses Intel Atom processors, but did I say it's 1.6 pounds! The screen is 11 inches and battery life is 3.5 hours, though an extended battery can be purchased to increase battery life to 17 hours.
Available now with Windows 7?: Yes
For more information on the Sony Vaio X Ultrathin Notebook, click here.
Photo Credit: Shane O'Neill