Netbooks have been a hit among laptop buyers because they're cheap and they're easy to carry. Now there's the option to pay a lot more and get a lot less a lot less weight, that is.

Sony's Vaio X is the runway model of netbooks: stylish, super-thin and without an ounce of weight to spare. It's expensive too: the base model is $1,300 at Sonystyle.com and Sony Style stores. The price is nearly four times as much as a standard netbook.

Its carbon-fiber body, just over half an inch thick, houses an 11.1-inch screen and weighs just 1.6 pounds. How light is that? Well, it nearly blew out of my hands one day when I was walking down the street with it opened. I'm not kidding. It makes 2.5-pound netbooks feel heavy. It makes the 3-pound MacBook Air seem like a dumbbell.

Sony says it's the world's thinnest, lightest laptop with a screen larger than 10 inches diagonally. Whatever the state of the competition may be, the light weight means that carrying the Vaio X around never really felt like a burden. It was a great companion on my commute, with a screen large enough to read comfortably on, and light enough to hold in one hand when standing, at least for short periods of time. For the ultimate in mobility, the computer has a built-in modem for Verizon Wireless' cellular broadband network. Service costs an extra $60 or so per month.

Of course, a mobile laptop isn't much good if it has poor battery life and constantly needs to be tethered to an outlet. The Vaio X does pretty well in this regard, at least if you consider the weight. On battery power, it lasted 1 hour and 47 minutes when playing high-definition video nonstop and accessing the Web via Wi-Fi. In more typical circumstances, this translates into about three hours of use.

The Vaio X also comes with a protruding extended battery with four times the capacity of the regular one. Together, you could get about 17 hours of work from them. The extended battery bumps the weight of the unit to 2.3 pounds.

The carbon fiber and aluminum frame is part of the reason the Vaio X can be so light. Like other netbooks, it uses an Intel Atom processor, which is small and doesn't run hot, so the Vaio X doesn't need a big ventilation fan or ducting to carry away heat. The unit also dispenses with the standard, disk-based hard drive. Instead, it has a "solid-state disk," or SSD, composed of flash memory chips that don't have moving parts.

The chief drawback of SSDs is that they have low capacities and high prices. The basic Vaio X has 64 gigabytes of storage. There's a model with twice as much for $1,500.

The small hard drive isn't likely to be a major impediment, however, because the Vaio X isn't capable of heavy-duty computing in any case. The Atom processor is good enough for e-mail, Web surfing and office applications, but will crawl when forced to do anything more demanding. Running the premium version of Windows 7 is already a bit of a struggle for it, and it doesn't have the processor power to play TV shows from Hulu without stuttering.

Other sacrifices to the design include feeble speakers and a somewhat flimsy feeling. The carbon-fiber cover isn't as good at repelling fingerprints as anodized metal or matte plastic, so the runway-ready looks can get grubby fast. The keys don't "give" much under the fingers, so extended typing can be uncomfortable.

The Vaio X does have a slot for SD memory cards, common in digital cameras, and an Ethernet jack for plugging into wired networks. Both are missing from the MacBook Air. The Sony model also comes with a GPS chip and navigation software, but I wasn't able to get it to work.

If you have the money and need something portable, the Vaio X is a nice choice indeed. Like most netbooks, it's best used as a backup for a standard laptop or desktop.