I would like the currency to be based on where the user is, as I think that would help with the conversation of interest into donations.
Then I could just choose the fallback currency for when this can not be worked out.
+1! I think people will be much more willing to pay in their own currencies. Particularly since I have a fairly even European/American audience. I have opted for USD for now, even though I am in the UK.
Can't believe this is missing still. The optional currencies are already there and IP detection is trivial.
Or as a first step, the option for the user to select currency.