The announcement of the Mac Book Air http://www.apple.com/macbookair/ which is just 2cm thick at the widest point is probably going to bring about a new wave of competing designs.
Looking at the spec of the device it seems to be more powerful than many of the mini PC laptops and weighing in at three pounds makes it pretty easy to carry around. Though the aluminium case looks like it would be best protected by a neoprone skin. In fact it will be interesting to here how people who travel with it get on - 5 hours battery life sounds good, my old Sony can manage 7 hours with its extended life battery.
Lets hope the the $1799 price tag has a reasonable conversion rate, at £900 it would probably rush off the shelves.
About the only thing that would be really good built into the Mac Book Air, would be the wireless USB system.