In all our years of travelling we've always taken the currency of where we're going with us. Either that or used ATMs/travellers cheques/visa until recently. This year however we have taken some currency but been able to get a better exchange rate once there. This has been in Turkey (not EU) and Spain.
Are we likely to find this in Florida? Somehow I don't think so but then I didn't think we'd get a better deal anywhere else until recently either.