I hate to sound like a shill for the Empire, but I swear to god, I get the best reception of my life with AT&T/Cingular. I get good EDGE/GPRS when I'm out of the city, and sweet 3G when I'm in town. I can even get reception in all of the tunnels under my employer's small campus, as well as the server room, and my office, which, though neither is shielded or tempested, contain a helluva lot of rebar in the concrete walls, enough to keep out most of the FM band for example.
It could be the phone, since I've had different receptions in the same places for the three Cingular phones I've had, namely a Nokia brick of the cheapest sort, a Moto RAZR V3 (the most basic model) and now my HTC Hermes (Cing/ATT 8525).
The Moto and the Hermes are both great at reception, head and hips above the Nokia (despite the Nokia's overt antenna), and the Hermes continues to impress.
I can't prove it, but I'd certainly consider the iPhone as a possible source of the problem.
There's also the chance it's a Boston thing...
heh, yes, that's quite possible.