Ultrabooks aren’t a hard sell. They’re super thin, really light, and powerful enough to handle everyday tasks (including a little gaming) with aplomb. That’s why I’d recommend them to students looking for a thin, light, and cheap way to get some great computing power without weighing down your backpack.To that end, we gathered up four promising thin-and-light laptops (called Ultrabooks in the PC world) including a fairly fresh MacBook Air and a cute little blue number from Lenovo. In the end, many of these laptops are approximately the same but there are some rules of thumb when it comes to picking a laptop.