The first thing you notice is that it looks like a normal MacBook; when it's open, you don't really notice the thinness - it has a nice big 13.3in screen and full size keyboard.
Then you pick it up, and you realise that the computer bit seems to be missing. The only laptop I can think of that felt lighter and thinner was the gorgeous but strangely short-lived Sony X505.
The MacBook Air tapers at its edges just like the iPod Nano, giving the impression that it's even thinner than the 0.76 inches that Apple quotes. It's pretty light, too, although at 3lbs it's significantly heavy than that old X505 and as heavy as the Sony TZ series, which features a built-in optical drive.
But hey, who needs optical drives? I think the idea of using the drive of a nearby machine is genius, particularly as it works wirelessly and (once software is installed on the machine with the DVD drive) will allow Mac discs to be read on PCs. It'll be interesting to see how slow this feels though - when you're installing a big software suite like Creative Studio it could take a very long time. Still, a lot of software is available for download now anyway, and this could hasten the death of the optical disk.
More of a hinderance, it my view, is the single USB port and total lack of FireWire and Ethernet. You can buy a USB Ethernet adapter, but then your one (one!) USB port is gone. Want to use a Superdrive? Better invest in a port replicator - and find a power socket to plug it into. And as for Apple's own FireWire... well, it was on its way out, but I still use it for video editing. Guess that's the end of MiniDV, too - I'll have to switch to a hard-drive videocam with USB 2.0 output.
Fortunately Apple has introduced the new Time Capsule wireless router/network drive so you won't need to plug in to back up. But nonetheless, can the MacBook Air really be considered a 'fully featured' laptop with so few connections?
This doesn't make me want a MacBook Air any less. The price (£1200 in the UK or $1800 if I'm lucky enough to still be in the states when it comes out here) is pretty good compared to the £1700 you'll have to pay for the Air's biggest rival, the Sony TZ. But let's not forget the Sony features an optical drive and a smaller form factor, plus an extra hour of quoted battery life, admittedly with a weedier processor.
I'll be honest: I'm looking forward to putting the two head to head. But for now, my lust for an ultraportable MacBook is sated.
Watch out for my video review, coming soon.