When I was abroad, the only credit card I had was an American express for students, and it worked really well. It really is accepted in most places, there are very few places it isn't. Although, the previous post is correct, mastercard and visa are better and more widely accepted. I also had with me a debit card with a visa logo on it. I suggest bringing the american express for the major things, like hotel or whatever, and using a debit for smaller things.