I'm in the midst of a big Euro trip right now and I'm currently in Krakow and I gotta say, if you want to party hard for really cheap and also check out nice old buildings and other historic sites (Auschwitz for example) then you should definitely try checking it out.
I've been here three times now, the first time I was basically a local cause I was staying with my cousin, the second time I did all the touristy stuff and this time I've basically only been partying and I have yet to be genuinely bored here so there is a lot to do. There are clubs literally on every street in the old town and they're all pretty big and busy and like I said, they're cheap as balls. If they charge you cover it's $3 and a bottle is $16-$40 depending on the club and liquor. I can't tell you how much drinks are cause I've been sticking to bottles but I know 6 or 7 shots came out to a good chunk less then $30.
I know it's probably not the best party city in the world or anything like that but you can really go crazy due to the exchange rate. All the prices are the same as in Canada but in Zloty which is basically 3 to 1. You say you might not care about money but you will if you're paying 10 Euro a drink like you probably will in some of the bigger cities that have been tossed around here.
Tomorrow I'm off to Madrid and then Barcelona, Ibiza and Paris, I'll give an update on those places later
P.S. I'm Polish and can speak it so that obviously plays a factor in my experience but Krakow is still a big destination so I can't imagine the language barrier will be any different than any other foreign destination city.