For all Germans out there or people who can open a bank account, [ComDirect][1]ComDirect bank issues a free visaVisa card that can be used in both countries without any fees and a good exchange rate. I used it in over 40 countries and never had to pay any fees except one time when I withdrew the equivalent of just 3 Euro. The fee was 16 cents or so.
Also keep in mind that in some countries you can notcannot use Western cards at all. Myanmar, Iran and North Korea come to mind. In Venezuela you could use your cards but you would get a rate that is over 100% worse than exchanging US dollar cash on the street. [1]: http://www.comdirect.de