Your story (OP) sounds like mine. I had a PowerBook G4 1.67, and I wanted to sell it before the new MBP's come out (to make sure I could get a fair price, especially since I crammed 250 GB into it and maxxed out the RAM).
That was my first mac, and I got it 3 1/2 years ago. Now I work full-time as a tech consultant and sysadmin, 90% of which is with Macs. (I think it speaks volumes to the OS by the way that before my AppleCare expired, I was able to intuit my way to the level that I did.)
The Air has blown me away. It's certainly an exercise in adaptability for a person in my position to deal with the connectivity issues (physical ports), but that's what AFP and NetBoot etc. are all about. The Air has actually forced me to expand my knowledge as a result of its limitations. There's more than one way to skin an Apple. Plus, since most of my job involves Apple Remote Desktop, Office, and the internet, the Air suites my needs as far as power goes.
Perhaps it's because I've come from a PPC 1.67 machine, but I think the Air is great. Even though I've got a week 2 machine (which I got for a steal on CL), I don't have heat issues... but I'll probably get it swapped out for a new one at the same time that I buy AppleCare as the case is warped and I've got some pretty noticeable deviations in backlighting.
BUT... I love the Air! And I'm glad to have been devouring all the threads I can in this section.