Check out this blog post by some lawyer in New York who loved his iPhone but had to drop it because AT&T sucked so bad. What put him over the edge was a call with AT&T customer service:

So I called A&T to see if their network was having unusual problems, especially in light of the fact that I knew they’d pulled the iPhone from their online store for about a day post-Christmas. Yup, I was told. AT&T has knocked down a bunch of towers in New York City and is in the process of re-building them. … Oh, and here’s the best part. They had no clue when they’d be ready to go. In the interim, New York City service is marked as “severely degraded.”