Just to follow up on the noise, if anyone's interested (or happen to notice this followup comment at all), noise is not an issue. I received my 13" about 24 hours ago, and only heard the fan briefly while it was syncing my entire Dropbox. Otherwise, it has been absolutely silent (and not even warm).
They had an older MBA sitting in a corner, which was hot enough on the bottom that I nearly dropped it.
The newer ones, which people had been using all day, were no warmer than my iPad gets (and significantly cooler than the iPhone tends to get).
Hard to tell about the noise. The store was too loud.