I waited for ages to get mine, when they didn't update it along with the new MBP line I just went for it ... and I love it. Yes - there will probably be an update soon, but for what I want - a system that starts up straight away, portability, ms word and a graphics card good enough for football manager 2010 - the SSD 2.13ghz model is perfect. It depends how desperate you are and what you really need it for - I think if people were that desperate for 4GB of ram they wouldn't be looking at a MBA anyway? (Not saying it wouldn't be nice to have it, but you know) ... anyway, as long as the next few versions of mac os x, ilife, ms office, and football manager work then I'll be happy - and with how zippy it is it should be fine.
Can anyone tell me if performance dips over time on this machine? I love how I can boot it up, and start using safari instantly ... but I remember being impressed with how quickly my old macbook started up but now 5 years later it's slow as s***.