Hows the coverage though? I know AT&T is cannibalizing EDGE spectrum for 3G HSPA and now even LTE so you might get worse GSM coverage vs 3G coverage...lowest I'd go is the iPhone 3G...I actually have my iPhone 3G out right now 
EDIT: YOur on T-Mobile nvm. Itll last a bit longer. Ah now I really want to go buy every version of the iPhone now....I'm thinking of getting a used GSM iPhone 4....I still think the 4 was the best looking phone...I have a CDMA one but a GSM one would be a little more satisfying...anyone want to trade?
EDIT: YOur on T-Mobile nvm. Itll last a bit longer. Ah now I really want to go buy every version of the iPhone now....I'm thinking of getting a used GSM iPhone 4....I still think the 4 was the best looking phone...I have a CDMA one but a GSM one would be a little more satisfying...anyone want to trade?