Anybody telling you to get an original MBA with 64 GB SSD is flat out wrong in even considering such egregious advice. The original MBA was problematic from DAY ONE!
I too spend most of my time typing on the MBA, as I do a lot of writing and consulting which entails writing. I absolutely love the MBA, and while the original may work for writing, it absolutely lacks the ability to work for all of the other things you might expect out of it, like watching a video or going to Flash based sites and etc.
The rev MBAs with Nvidia GPU, and Penryn CPU, and SATA-II SSD, and DDR3 RAM, and etc, are powerful enough for today's work and for several years down the road. The original is already lagging, and requires lots of extra maintenance.
I wouldn't believe you would honestly take the advice, but I must tell you per value, even $499 wouldn't make it a worthy value versus a rev C at full price brand new. I highly recommend either of the Nvidia GPU MBAs with 1.86 or 2.13 GHz and SSD. To get the absolute best performance you need the SSD. It eliminates waiting on your MBA, which is what the HDD owners do (likely 5x as much). The SSD is the amazement that takes the MBA from an ordinary ultraportable to a fast notebook like speedy Mac.
So, I don't know about your options where you are, but in the US the MBA is $1549 2.13/SSD refurbished and $1349 1.86/SSD refurbished. I would say if you cannot afford one of these, you reconsider your decision to go MBA.
A lot of people who are happy with their HDD models are using them as secondary Macs. I am using my 2.13/SSD as my primary Mac and sole machine. It never lets me down. I absolutely love it.
I would say if you can wait for a few more weeks, we might learn some rumors for when the next MBA will be released. I think it is very likely Apple will update both the Mac notebooks and iMacs before the holiday season! It really makes sense to keep updating Macs in this economy to continually improve reason for people to upgrade. The point is if you know you can wait until November, it may be worth your wait. At the same time, there isn't much money to lose on an MBA at the refurbished price points we currently have... you will not lose much at all from today's price if you sell and rebuy a few months down the road. The pricing is ridiculously low for the MBA right now. In the past, people were losing more money on their MBA's than any Mac I can recall reselling.
An MBA released in the next few months may include a new GPU, same CPU, 4 GB RAM, 256 GB SSD, and a glass trackpad. It may also cost a lot more!!! So take that into consideration. Apple would need to recover the high cost of the SSD, and the price point will be a lot higher than the current $1799 brand new.
Also, definitely consider a few other things... 24" LED ACD, Time Capsule (AirPort Base Station w attached drive), and MobileMe. All make the MBA experience a true Mac experience.
An MBA next year may bring anything from new form factor to super powerful MBA to anything. So, if you need it now, buy it now and don't worry.
Good luck.