Actually, if you have a BofA ATM card, you can use it at any Deutche Bank in europe without any transaction fees.
BofA has a partnership with Deutche Bank, and there is no transaction fee if you use their atms. Finding a Deutche Bank in Spain was surprisingly simple.
As far as credit cards, all of them (Amex,Vis,Mastercard charges an exchange fee. I think it's roughly2-3%).
I wouldn't recommend traveler's checks. Major PITA.