Outside the UK (Germany, Spain, etc, etc) you may come across restaurants/stores, etc that WON'T take credit cards, only local debit cards.

This is where having an ATM card comes in most handy - as nearly any US ATM card can work at most European banks.

Why don't you consider getting a Visa or MasterCard Debit card (it's an ATM card BUT can also be used at traditional credit card accepting outlets - the funds are just debit'd right away from your account)