Looks like Cell Phones Service is getting /. pretty hardcore right now (http://slashdot.org/article.pl?sid=03/08/04/1122252) ... interesting read -- Trying to determine the best service in an area is hard, and I think varies by phone and expecations.  I used to have AT&T in the southeast and it was miserable, but when I traveled it was normally the 2nd best or "good enough."  Now I'm on T-Mobile, it is "good enough" but I wish it could be better.  At least I don't have sprint.  Best news ever is the new law in november that enables anyone to keep their # across providers, what a deal! 

The BEST thing that came out of this thread though, is this wireless tower locator that lets you map out the towers near you by providers, etc.  Way better than a coverage map...