Air owner
... and I love it. I got a previous model when the new models were announced, so I got a pretty good deal on it. It's not meant to replace my workstation, but as my mobile machine. It is very light and surprisingly well-built; certainly, it's more sturdy and less flimsy than the think slab of HP EliteBook I have to use at work.
The whole idea of the Air is complete mobility. Reduce weight, keep out the things you don't need, and make it a computer that is useful three years from now. Hence, no ethernet. With WiFi so common these days, do you really need that? I have yet to use the USB port on mine once after half a year of ownership, so that's no issue. And I was surprised how little I missed the optical drive. After an install initially, using the drive on my G5 tower, I haven't needed this once.
Apple has something of a history of this. Remember when the original iMac came out? Two of the biffest negatives were: it didn't have a floppy drive, and it used USB for everything. One year later, USB was everywhere (thanks largely to the iMac; there's a reason all those USB devices at the time were blue and white). And people realized that the floppy was not really needed, unless you had to make a boot disc for some cheap hacked-up ... anyway.
As I said, it's been a great machine: light, sturdy, reliable, and very quiet. In my life, I will take all the quiet I can get.