I have found places in BC that don't take VISA but do take MC and some vis-versa...merchant fees, I was told. So take both, wouldn't even bother with a Discover. Provincial Parks don't take US checks or credit cards so some cash is needed for those fees. In BC at least they are OK with US currency and will just round up, or down, in their favor, the exchange rate. (Sad that we won't extend the same courtesy when Canadians visit the US isn't it?) You get out in the sticks in Alaska and you can find places which only take cash also. Good to have a few hundred on you if you are going to those places.