Friend of mine bought one right from the Best Buy store with no contract for 549.99. You could save 50 bucks and get it from a retail AT&T store. Not sure how Best Buy is with warranty issues in the first 12 months. Never had a problem exchanging phones in the AT&T stores.
I was kind of surprised all the Best Buy display models were fake non-functional display units! Kind of hard to get a feel for a new phone if you cant even demo it and get a feel for the UI.