When I was in Italy in Sept. I went to a Travelex exchange place because we were running low on cash. Their poor exchange rate plus their commission (17%, the fuckers!) would have netted me a 50% exchange rate, i.e. 150 euros for 300 bucks.
I told them that their rates were unacceptable and took the money back. The attendant said "It doesn't matter where you go, you'll get the same rate. We own them all." to which my response was, "Then I'll do without the money."
It turns out that the best place to change cash in Italy is the _post office_. I tried to exchange money at a bank and they were willing to do small amounts, but 500 bucks was too much. They sent me to the post office where I received an exchange rate of 71%. The best I had done in Amsterdam was 72%.
By the way, the best exchange rates I have found in Amsterdam have consistently been from that little hole in the wall office on Damrak. It has a Western Union sign, but the exchange place isn't actually Western Union. It is just a little south (away from CS) of the Mannekin Pis frites stand and immediately north of Dam Hotel/Marco Polo Pizzeria