Leave it in your bank account. I take US$100 tops in cash for incidentals.
Use your debit or credit card for all purchases. Works especially well if you have a credit card that does not charge forex fees; that is really the cheapest option. Some of these even offer cash back. Not enough time to get one if you don't already have one. Otherwise, I personally would bite the bullet and exchange at my bank (go to a major branch if you have a lot). Sometimes an airport kiosk may have a better rate; but IMO usually not. Note another recent thread here; if you have over $1000 you get a better rate at the bank. But seriously, don't go down carrying $1000 cash...
One other tip for cards, I always have two different payment cards. Leave one in the hotel safe in case the other one is lost or compromised.