Several years ago we were planning a trip to Europe and I asked our local travel agent a similar question. She responded with the following:

#1 Double check your destination to see what kinds of credit cards they take.
#2 Make sure you have one of those cards.
#3 Do a simple multiple of the nights vs the room rates and add that to meals and transport, then make sure that your card will hold that amount + 15% for emergencies
#4 Take a surplus amount of cash for incidentals. This is best done in travellers checks which you should entrust to the front desk safe (if they have one).

charles
arubafastphones.com