I am in a similar situation. I have a 17" MBP, but I bought it nearly a year ago when I was doing a lot of photography & 3D modeling. These days I pretty much just use it for the web, mail, iPhoto, iTunes & iWeb. I travel quite frequently, so an ultra portable would be nice. Also, I never sit at my desk at home and am either on the floor or on my bed or in a chair with my MBP.
So needless to say I bought an MBA, but have yet to crack open the box as I had some reservations that it was an impulse buy. But after evaluating the situation, I'm leaning more and more towards keeping it as my only computer and selling off the Pro. For my needs it's all I need.
And yes, I realize I could save money by going for the Macbook, but I'm a sucker for aesthetics and good engineering. I recognize all of the effort (and money) that went into producing the MBA, and am willing to pay a premium for that.
BTW - I also ordered Time Capsule
Don't get me wrong, I also recognize the effort they put into designing this computer. I recognize the fact that they have to reduce the processor size to fit it in and all that stuff. But, why is that my problem?. Why do I have to pay extra for less?. Because at the end of the day, you end up with a computer that lacks connectivity and horsepower, just to be thin. And, seriously, all they did externally in terms of design was making it thinner toward the edges. I don't think that deserves a design award, do you?.
Anyway, they released this computer because there's a market for it, and I bet it is not the guys who need an ultraportable, the ones Apple was thinking of when they released this computer, but the guys who would buy this computer just for the aesthetics (nothing wrong with that).