I, for one, rarely take any more money to Europe than is necessary for initial tips and perhaps a cab. The Euro has made life wonderful on the continent and in my experience the best rate is from the ATM. You should check with your card issuer, but mine gives me the Interbank rate plus 1 which is about as good as you can get. You should make sure that your PIN is no more than 4 digits and some ATM's will automatically limit your daily withdrawal to about $200 or $300 USD. We just spent two weeks in Spain and Portugal and I believe that my cash needs were less than $500. Visa and Mastercard are accepted everywhere, but they are loathe to accept American Express (the latter's fees are higher than the former).

If you go somewhere that is still using local currency such as the UK, then a good place to get a little conversion table to carry in your wallet is http://www.oanda.com.

Tom in a very wet Carlisle.