I've had a MacBook Air for the better part of a year now and been very pleased. With Bootcamp it's trivial to install and run Windows 7 and it's been one of the most reliable, predictable laptops I've had to date.
In fact, my only real complaint -- and it's a big one -- has been the low success rate when using the standard Apple Mini DisplayPort to VGA adapter with the various projector configurations at work. A majority of the time the machine simply won't drive the external display.
Finally, thanks to a thread on apple.com, I discovered a pointer to the Cirago Mini DisplayPort to VGA Active Adapter (DPA2011)
I'm delighted to report a 100% success rate so far!