I've always thought using my credit card is the best, but I decided to avoid using it.
First, the additional exchange fees. Discover has none, but it is not widely accepted. Second, the crappy exchange rate. I found out that my bank's fees for buying traveller's cheques will come out cheaper than that of what I'll be losing from the credit card exchange rates. Note that the traveller's cheque cards work like a credit card with a crappy exchange rate. They may have additional fees, too.
I finally decided to bring paper travellers cheques and cash and use my credit cards as just a backup.