I'm an expatriate and live on the road; I'm literally never anywhere without my laptop, not even for five minutes, so the weight and form factors are critical. And I don't use my computer for entertainment, and don't care about having a DVD drive, etc. I do all my development with Flex, Dreamweaver, Dashcode and a LAMP stack, so my needs may not match those of desktop app devs. But for me it's really been ideal.
Some of the advantages of the Air include the fact that the screen resolution is better than my MacBook (but as I'm used to the MacBook resolution, it's what I currenty have, I'm sure I won't miss it)
SSD drive, but I'm thinking that that is more about headroom on my MacBook Pro. In a couple of years time when it starts to feel a bit old and slow, I'll pop in an SSD (which should be cheaper by then), and my machine will get a new lease of life.
Just as an aside, my use case is mostly centered around programming in XCode and Textmate, but this is my principal machine at home, so lots of web surfing is also done.
You are so right on video, it really needs a bigger machine.
I think the biggest difference this time (I have used a MacBook Air in the past for dev until I switched to 17" MacBook Pro) is the added option of 4gb of memory. That will really help. Also, the lack of heat right under my left arm would be a nice touch.
// do not buy the official external drive - it doesn't work on other machines
So if I want 4GB of RAM, Apple it is.
Isn't the fact the RAM isn't user-installable (true) in the MBA even more reason to buy the full boat?
I do iphone development, so I'm stuck with what apple has to offer, but if I didn't that would be my machine of choice.
Also, to the poster who wrote about the MBP vis-a-vis video...Yeah. Firewire is what's missing from this machine. I don't do any video work at all anymore so it doesn't bug me. But it would.