chemist - I know that place at Bradley/LAX you're referring to. I may seek out a similar one at Miami Intl., although bank locations at the airport will probably be better.
St.Seb - thanks for your points, especially about watching out for the surchage on credit card use. But as far as where to exchange $/Euros, the rule of thumb is typically to get the "foreign" currency you want before you leave the location of the currency you want to get rid of, i.e., get a better rate from an American bank for Euros than handing dollars to a European bank?