Backlit keyboard on it and I am in. Perfect form factor and feature set for what I do all day every day. And less weight in my bag
Currently have the 13 mbp and would love to get a MBA to lighten my load.
I've heard this request from a lot of people on this forum. Is this really a deal breaker for you? the screen isn't bright enough at night to illuminate the keys that you need a separate source of light?