Regarding the credit cards:

I lose about 3% on credit card transactions in other countries.

I lose only 1% on ATM withdrawls in other countries.

If you use a card that gets you great benefits that equal or exceed 2% (like airline miles or cashback rebates), then use the cc.

The above rates are compared to the interbank rates that the banks exchage currencies at. Different credit cards have diffferent markups on forieng transactions. My Amex and Visa cards lose 3% but others are reportedly different.