How about the fact that AT&T service stinks in many people's home areas? I can't get a signal from AT&T at my home and I'm all cellular - no home phone for years.
What most people don't know.. is that AT&T is in process of building hundreds of GSM/Edge cell sites just for the iphone project, including microcells (minature cell sites) that will operate at every Apple store. This mass build of cell sites isn't just to increase call capacity either, many dead signal areas are going to be covered/improved. Apple wouldn't sign a 5 year contract with a company thats going to let the older 2G network drop off the face of the planet. Now, why Apple decided to go with a GSM/Edge phone versus a 3G phone of sorts, is completely beyond me.