what money to take?

I bring a couple hundred USD, primarily to pay the parking bill when I get home and buy lunch and sundries at US airports, and whatever GBPs or Euros leftover from the last trip. Bring ATM cards from 2 separate banks to get cash in the local currency from Atm's along the way.

Sam's answer is perfect and covers all - that is ALL you ever need to bring. If you have no Euros left over from a previous trip, no worries, you can get them easily at the airport upon arrival. Bring a little local currency home with you for your next trip.

'If you have no Euros left over . . . ' Those suckers won't go very far in England where the expedition begins. 'you can get them easily at the airport . . . ." Not very economically. Here's what you're going to find: a. Both of the major London airports have only TravelEx currency exchange facilities. They have a pretty rotten exchange rate. Not that big a deal since you can just get a hundred bucks worth of sterling, and get more from atms once you get into town. b. There are bank atms at Schiphol where you can load up on euro.

Rely on using cards at ATM's. Much, much simpler and safer, and typically the cheapest. I usually buy about 100 pounds at my U.S. departure airport, whatever the rate. That allows me to get into London, into my hotel, and on the street the next morning without worrying about cash. It's not absolutely necessary, but it allows me to get out of the airport and to a hotel ASAP at the end of a long and tiring day. Remember, if you pull a wad of cash out and take it with you, someone can grab it and you are stuck. But, even if someone grabs your cards, you can phone back to the U.S. and arrange for emergency funding. (So.. write down your account numbers and the toll-free phone numbers of your account issuers and keep it someplace that is NOT the wallet with all of your cards.)

'The 800 numbers don't seem to work from overseas.' Sure they do. You just get a recording at the start which says that, if you proceed, the call will be at the regular rate. 'Most credit card companies will take a collect call from you...' They all do. It's an automatic answer (no human decision involved) with the charge going to the receiver's account - - just like an 800 number does.