I have the 13" 2010 air (purchased in Jan 2011) and swear by it. Toss up for me at the time was the Air or the Ipad 2 as I also have and all bells Alienware I7. The Alienware is now a doorstop, Air travels with me everwhere work, play reading does it all, even some World of Warcraft on the move. I have changed the SDD for a OWC unit with Sandforce controller which is a nice but brutally expensive upgrade. Only mistake I made was not getting 4Gb ram but to be fair that also has never been a major issue and was only a BTO unit at the time I got mine.
The refresh with the I5/7 looks great, as does the backlit keyboard, am not impressed with the variations in quality of the SSD's and screens but would one even know unless someone said so. What is stopping me getting one is Apple's use of the crap intergated Intel GPU. If updated drivers improve its performance or Apple bring in a model with more graphics firepower sign me up, you won't ever need a Pro then.
And i would recommend the 13" save your eyes!