That said, I usually quote a higher per-word rate for clients in countries with favorable exchange rates, but I still quote in dollars. I update my rates on my rate sheet once a quarter usually to reflect any major changes in exchange rates.

I’ve almost never had a client balk at this; it’s as easy for them to do a wire transfer for a dollar amount as it is for a euro or yen amount because the bank forms allow you specify the target currency. On the very rare occasion it does pose a problem, I convert the invoice to the foreign currency at the exchange rate on the date of invoice, which is fair enough in most cases.