How much spending money should I take on a 3-wk trip to europe?

I would suggest $40-50 per day at least. Remember that Europe is more expensive because the US dollar is so weak right now. It is always better to have too much money than too little. Most places accept credit cards, however in Europe cash is more used than here in the US. But get travelers checks here in the US by your bank (can only be cashed by you, even if you lose them, no one else can cash it) than can be cashed at any bank in Europe. ATMs works well, however remember that you will get charged a currency fee by your bank and also a fee for taking it out of another bank than Bank of America. Also, usually tip is included in all services like restaurant bills etc in Europe. You do not tip unless the service was extremely exceptional. I was born and raised in Europe, and I don't think I ever tipped more than a handful of times in 28 years of living there.

Definitely use the ATMS and don't carry lots of cash. One pointer: call your bank first to let them know you are traveling overseas. If not, they may block your card after you use it a few times thinking it is stolen (this happens to me occassionally and I've lived in Italy for 10 years!). Also be sure that they up your daily and monthly limit for the time you'll be gone so that if you are in a pinch you can get money. And not all banks charge heavy fees -- even so, you get the best exchange rate. I always tell people to take a little money in traveler's checks but use them as a last resort because it is costly to exchange them. And whenever you can, use your credit card to shop. Although if you are buying local products you'll often find merchants in small stores won't take credit cards. Lastly how much money should you bring? Well, if everything is paid for I'd make up a list of everyone I want to buy something for and allocate about 15 euro (about 20 US dollars) per person. Then I'd add another 20 euro/day for incidentals. And then I'd expect to spend another 100 or so for impulse purchases.

Take loads of money, europe is expensive, due to the euro, and the dollars weak.The banks will charge to change dollars, as will the atms.

I would say 60USD a da because Europe is expensive.

Definitely DO NOT take cash!!! There are plenty of ATMs in all the above-mentioned countries. As far as $20 per day USD, I would suggest doubling that at least! You are going to see things you will want to buy, as well as do some extra things! You'll probably be walking alot and get thirsty, hungry, etc... Souvenirs are much cheaper in general than the U.S. but you just never know, so I would plan for $40-50 a day extra.

most of the above answers are correct. Traveler's checks are perfectly fine. Go to any banks to cash them. Don't buy things with them. The most recognized are American Express, Thomas Cook and Visa Traveler's checks. I would recommand about € 1,000 (USD 1,300) for 3 weeks on the safe side (seems a lot but it is better to have extra than having a shortage in case of emergency)