I'm not an AT&T apologist, but I've gotta say: In eight years with AT&T, I have not had any major issues with reception. In the past few years, I've been all over the Carolinas, VA/MD/DC, NY/NJ, CA (LA, San Diego, and San Francisco), Florida (Miami, Tampa, Orlando, and Jax), Houston, Atlanta, Chicago, Las Vegas, the Caribbean (you name it -- just about every island), Mexico, Europe (I know, not AT&T, but it's GSM), and I have yet to experience a major problem. I honestly do not understand all the complaining about AT&T.
I did have a problem with my iPhone 3G dropping calls after it first came out, but Apple fixed it with a software update.
Maybe I've been incredibly lucky... or maybe some people like to complain too much.