I'm planning to buy one too, think I'll wait for the update. have a EEEPC at the moment, which will do while I wait.
Patience is the golden rule with apple. Remember it's a 1300,00 (more or less, depending on model) machine you're buying, if it updates two days later, will you not care?
I compared the Air and Pro, both the 13', both with 128Gb SSD, both with 4Gb ram, only the air had a 1,8 GHz processor and the pro a 2,4.
pricing: Air -> 1305,something
Pro -> 1376,something
(with the student discount that is)
I'd wait for the update and see what the Pro does.