Does nobody else just jump in the shower with their underwear on and scrub away?
Everyone else seems to have covered the bank front but just make sure you hide a stash of cash in you bag at all times incase you lose your card or it fails at any place.
If you want to get a clear grasp over Europe, then it´s recommended for you to visit the cities that I´ve mentioned below;
The reason Barcelona is a must visit, is that you would be already in Madrid, Spain and Barcelona is quickly becoming one of the sought after cities of the world!, let alone Europe.
Also, the period of time that you´ve mentioned should be more than enough to be able to see, witness and experience the best of the above mentioned cities!
If you have to compromise this list, just know that Barcelona is simply a must! You´ve got it all, great architecture, modern shops and districts and the beach!!!
Then comes Rome, more than enough has been said about this city, if you want to get lost and caught in time, then look no further. Just walking along this city will be an attraction all within itself as it´s completely filled with monuments and attractions everywhere you turn.
If you want a more detailed plan on the activities and attractions of rome, then please visit the following website;
They provide a list of ways on how you can experience the city.
If you want to head up north to cities like Berlin, Paris or Amsterdam then keep in mind that it´s significantly colder compared to countries like Spain or Rome.
I think the cities listed below are a pretty good sampling. I would definitely hit Paris and Rome, and have heard great things about Barcelona and Berlin. I also had a great time in Prague. It kind of depends on exactly what you are looking for. I also love, love, love Ireland and Northern Ireland, but it might be a bit easier to stay on mainland Europe.
As far as getting money be sure to talk to your bank and/or credit card company ahead of time. Some charge you hefty fees for ATM transaction overseas. It's definitely best to know this up front
I'd bring a quick-dry camping towel. Some hostels will have them, but others may not. As long as you aren't allergic, etc. no need to bring detergent, as said before it's easily accessible.
If you want the ease of a mobile, then go ahead and get a sim card, though you could also skype and buy calling cards as suggested before. Now there may be a way to avoid this, but when I had an Irish sim card, it worked other places in Europe, but it cost me more.
Go to the Visa/Mastercard central site and they list most every ATM that can be used worldwide. Many European ATM's do not have an alphanumeric keyboard, so memorize your PIN in numbers if you use alpha like I do. Winter in N. Europe - burrrrr! You might want to spend some time in Britain as well since the Pound has just been devalued and you might as well take advantage before it rises again. Personally, I like Norway the best of all (also the most expensive these days). I don't believe Europeans use credit/debit cards the way we Americans do - they wouldn't think of buying a 6-pack with a cr card, but we do it all the time! Tell your banks where you're headed! In Europe most everything revolves around the central RR station - why can't we come up with a system like that? If you like your beer and pork, head to a German Rathaus (city hall) - you won't have to eat again for a week! I like Paris, Amsterdam and Copenhagen.
Just in the off-chance that you are using Citibank: Go to their website and look up the international Citibank ATMs and branches. Make a MS Word file with the locations of Citibank ATMs in the cities you might visit then print it out. Withdrawals are free of fees if you have a Citibank account, you can even use your standard ATM card.
Citibank might also be your last chance of getting money if you use another US bank, so it is good to know where they are.
Re: 3. It is a good idea to carry some detergent. It can be a hassle trying to find detergent in small packages, especially on a Sunday morning when you really need to do some laundry. I like to use tabs, powdered detergent pressed into a big pill. Buy a whole package at home, then take 2-6 detergent pills with you. And yes, bring a towel.