For us it depends on the present exchange rate, but typically I don't exchange for euros with a local bank. Keep in mind that currency transactions rarely (if ever) mimic the exact rate of exchange. Banks will protect themselves from fluctuating rates by adding in a fee or adjustment to the exchange percentage. For example, if we decide to bring 200 euros with us our local banks should charge about $227 USD at today's rate. But, they won't. They'll pad this a bit and reduce the exchange a few points so it would cost us about $233 based on past experiences. Keep in mind that currency exchange centers -- like those located in international airports -- are even worse.

As ruralcarrier described above using a credit card ensures the proper exchange rate, as long as your bank does not charge a foreign transaction fee. So many people are getting ripped-off by that particular bank fee!

But, the caveat on French St. Martin is those places that don't take credit. So, what do you do? Unless I'm certain that I'm going to doing some heavy dining at the french restaurants I still stick with U.S. currency and forego bringing any euros. The most I was ever charged for paying in U.S. funds at such restaurants in recent history was $1.10 USD to 1 euro which still made paying in dollars a smarter choice. I believe that was at Ocean 82 restaurant in Grand Case about three or four years ago when the exchange rate was at .86 to the euro. Also, I never took a taxi ride on SXM that didn't accept U.S. currency. Among the taxi drivers that was the standard.

One last note. If you plan a day visit to St. Barth's then I would bring some euros. The approach is definitely different at many places on that neighboring island.