Lastly, there’s Lenovo’s LaVie Z, a 13-inch laptop that holds the distinction of being the world’s lightest, weighing just 1.7 pounds. Nearly everyone says the same thing when they pick it up: It feels like a hollow shell. It gets its feather-like weight from a magnesium and lithium alloy that Lenovo says is 50 percent lighter than aluminum. Battery life on this machine won’t last you all day, but the company says you should still get about six hours on a charge. While this is the lightest full-sized laptop at the moment, it will also be heavy on your wallet; Lenovo says it will be start at $1,299 when it goes on sale in May.