The Netherlands uses the Euro, the same currency as in the adjacent countries Germany and Belgium (and France, Spain, Italy, et al.). ATMs are widely available; they invariably accept the large American networks (Plus, Cirrus) and allow you a choice of languages. Credit cards are widely accepted at hotels, restaurants and tourist destinations, though not at many shops (except those catering to tourists, department stores, etc). Supermarkets never accept credit cards!

Amexco (and some banks) now do cash cards in many currencies.  So, instead of carrying travelers checks in Euros (or any currency) you might consider buying the cash cards.  They can be used like any debit card and are protected by a PIN.  Some shops in Amsterdam accept Euro debit cards (look for the Maestro sign).