Don't listen to Scottsdale. The Rev A is a great machine. He had a bad experience with one ages ago, so now he spends most of his time on this board hunting down threads about the Rev A and bashing them to anyone who will listen.
If you are getting one used, does it still have any warranty left? If not, but you still want a less-expensive Air, you should strongly consider going the refurbished route via the Apple Store, or offer the seller quite a bit less. If they are going for $999 new (for all intents and purposes) with a full year's warranty, plus the ability to buy Apple Care if you really wanted to, a $149 "discount" on a used machine is probably too much.
Not true, these threads here have been full of people who had problems with their original MBAs. I personally know ONE person that still has an original MBA, when I knew MORE THAN TWENTY who moved on (mostly to rev B). It wasn't the double the drive space. It was before Cool Book was widely known, and the MBAs overheated just playing video for five minutes. There are a few happy with their original MBA, but most are using Cool Book and/or have reapplied the thermal paste.
Also, my track record on honesty of the MBA in all its revisions is pretty damn good. I have owned all three. For someone wanting to use an MBA as their primary Mac, they absolutely MUST go rev B or newer and SSD. The HDD is just no fun as it's really slow. For a secondary Mac, for LIGHT web browsing, email and Pages, sure the original MBA with SSD and Cool Book is acceptable. Maybe even rev B (or newer) with HDD is good too.
Those of you that own the original MBA, who bought it refurbished, have a completely different measure of value. When you pay $999 your value decision is far different than the original MBA buyers who bought them for $1799 to $3099, only to not be able to use their MBA as a light secondary Mac, as even for light video use, disappointment set in quickly.
The original is for some, but I prefer "It just works," and that is the rev B or new MBA. Fast is SSD (even with original). So it all depends how you want to use it.
Personally, I disagree with some of your posts, but I don't go saying don't listen to them! That's really disgusting when we are all just trying to help someone out. What would you tell your brother or sister or mom or dad or best friend??? I WOULD NOT RECOMMEND AN ORIGINAL MBA TO ANY OF THEM ESPECIALLY WHEN COMPARED TO THE PRICING NOW ON A REV B WITH SSD FROM APPLE FOR $1449!!!