I don't know in Uk or USA, but in the rest of europe there is no difference at all in protection against fraudulent charges between a credit and a debit card.
There's no difference with fraudulent charges in the UK, as far as I'm aware, but when you buy a product or service on credit, we have a law saying the credit provider and retailer are both liable.
This means for example if you buy a flight and the airline goes out of business, your credit card provider will need to refund you. Also if goods are faulty, you now have two possibilities to get your money back - and the credit card companies are usually more amenable.
