Cash in the US - withdrawal or exchange?

We took cash from our bank and used Visa to pay bills like meals and gifts in shops very little we needed cash. You can find exchanges there I believe but I'm not clear how the rates are now. Also maybe possible to go into a bank there and get money out on your card.

Exchanging currency for dollars in the USA will be your most expensive option by far. Make sure you inform your card issuer of your travel plans or the chances of you finding your cards blocked are very high indeed.

Avoid using your Belgian cards for small expenditures as there will be fixed transaction charges as well as a much less advantageous exchange rate.

I've actually found the cheapest way to go is to buy USD cash here and then load it onto a prepaid credit card in the US.

You need to be very careful where you buy the cash. Most Bureau de change take very wide spreads, so it's often not worth it, but you can buy USD cash at Eurogold (down by the Bourse) at a 20 bp spread which is far, far better than any spread you'll get from a bank or credit card.

As Mikek1300gt says, make sure you inform your bank before you leave that you're going as many banks by default block their cards for use only in the EU, by letting them know, they can adjust your account to show you'll be using it somewhere else.

Yes! Essential to ask your bank to extend your card's range beyond Europe.

Also, you can purchase dollars from your bank (at least I can at KBC - you probably will have to make an appointment or come on a particular day of the week) for the best rate.

Yes .Eurogold has definitely the best rates in town and a plentiful supply of a wide range of currencies.