I just watched the photos and text from today's keynote at MacWorld. Steve Jobs unveiled the MacBook Air, described as the world's thinnest notebook computer. I suddenly recalled being at a computer graphics user group at UCSC, circa 1982.
One of the hobbyists in that group had a Sinclair ZX80, a kit computer from the UK that was notable as the first personal computer available for under £100. The thing that makes me think of that early PC in relation to Apple's new notebook is that the ZX80 was even smaller and thinner than a MacBook Air. We usually think of early PC's as chunky monstrosities like the Osborne 1 or the Commodore PET that nonetheless cost over $1500.
It's interesting to recall that more than 25 years ago, the $100 portable computer was a reality, though with far less computing power than a modern alarm clock.