Would you suggest buying the iPhone at the Apple store, or at an AT&T store? I've heard that the employees at the AT&T store will do a better job of setting up your AT&T account.
Based on the zoo that I witnessed on multiple visits to the Apple store, I would suggest you get set up at the AT&T store. The only problem I had was having to wait "7-10 business days" (which was actually only just 3 days before Fedex delivered my iphone

). It took a couple of extra days for my wifes iphone to arrive (I got the 32gb and she got the 16gb - must be a higher demand for the 16gb).And if you do the AT&T store, I would highly suggest that you make an appt over the phone (or else you'll get stuck putting your name on a piece of paper and end up standing around for a long time).