Speed test puts my iPhone 3G at 1.79Mbps in Tallahassee, FL (state capital)
Buddy of mine was flying through Tampa yesterday and said he was getting pretty strong results there too... I dunno, maybe AT&T beefed up their 3g service in Florida for all the retirees with their iPhones...
All I know is that I can't get a decent signal to save my life in Chicago...