Are you looking to use a Debit Card to simply withdrawal cash from an ATM at an international location, or to actually use at merchants for transactions?

I would argue to not use a debit card at merchants for transactions for multiple reasons:

• You should not carry your debit card around with you at all times, only when you need to withdrawal cash at an ATM.
• In some countries, your card # or physical card can get stolen and erroneous charges placed on it. This has happened to my credit card multiple times and I have never been held liable for the charges. The same might not be true with your debit card - the protection you have just isn't there when it's your actual funds in the account. Just keep a secondary credit card in your hotel room and you're good to go if you need to ditch the main one.
• There are many credit cards, some with no annual fee, that have no Forex fees at all and also give you points for all purchases made! I have a few Capital One cards, including the no Annual-fee VentureOne Rewards. I also have some Chase cards that carry an annual fee, but give me benefits at the Marriott and ICG hotel chains. There's no reason to not use a Visa (accepted much more than MasterCard) Credit Card that has no Forex fees and gives points to boot when travelling overseas.
• As a side note, when you get your credit card with no Forex fees, always always always make sure the merchant charges you in the local currency and not the USD "equivalent". The latter is a scam that nets them some cash with a crappier exchange rate for you. This happened to me once, even though I checked the box for Indian Rupees and not USD, and it came out to a $50 USD difference on a 2-week hotel bill.

Also, there are many banks that offer a Debit/ATM card that carries no fees at all when used at international (or domestic) ATMs. I have a PNC Bank Performance Select account, which requires me to hold an average monthly balance of $5K USD, but I do not pay fees for anything at any ATM domestically or internationally. It does carry a 3% forex fee when used at merchants, but as I state above, I don't use it at merchants.

It took me many years of traveling to sort out all the above, and I cringe to think of all the Forex fees I paid before I sorted out my credit cards to use internationally.