The black Toshiba Portege Z20t combines a slick-looking tablet with a superslim keyboard deck for a sleek 2-in-1 design. The 12.5-inch, 1080p display provided bright and crisp images in our tests. We also loved the Portege’s included Wacom-powered stylus. This two-buttoned accessory works seamlessly with the laptop’s 10-point multitouch display for surfing the Web and taking notes in tablet mode. A smaller emergency stylus also sits on the bottom edge of the tablet. But the most eye-popping detail of this elegant machine is the battery,