Lenovo's made the most of the time since Intel defined the "ultrabook" last fall, releasing a number of different models designed for different users. By and large, the company's done good work, too: we called the ThinkPad U300s the best ultrabook on the market back in November, and the IdeaPad U310 delivers pretty solid value for $799. But Lenovo saved its best for its latest, the ThinkPad X1 Carbon. The Carbon is the successor to last year's X1, and ticks all the ultrabook boxes, but it tries to go even further and outdo everyone: it's a 14-inch laptop that's barely bigger than a typical 13-inch model, and its carbon fiber body is less than three quarters of an inch thick and weighs all of three pounds. There's no shortage of power inside, either, thanks to a Core i5 processor, 4GB of RAM and a 128GB SSD in the base model. Solid specs and excellent design add up to Lenovo's most premium ultrabook to date and also its most expensive: it starts at $1,399 and you can easily pay $500 more. Lenovo's laid all its cards on the table, and put everything it's got into one machine. Is it enough? Read on.