I mean no offense, but it seems like people really don't know much about PayPal... I use it almost exclusively for my banking... someone made a comment about 'free' PayPal accounts and limits thereon- there's no other kind. And I have no credit cards, but have a full PayPal account (and a PayPal debit card).
And there's no conversion that has to occur to send Euros to Wikimedia. When you send money, you can choose which currency it's sent in (though if your account only uses Euros (which currencies are used in your account is strictly up to your control), it'll be sent in Euros). If the Wikimedia account is set to accept Euros, it'll add to its Euro balance (if you accept multiple currencies, you have separate balances in each, but can transfer between them at any time with no charge), otherwise it'll automatically be converted to dollars.
Someone mentioned the Maestro system- it's worth noting that's MasterCard's debit system. There's a large degree of interoperability there.
Just some notes.
--Jake