Hmm

Belgium (obviously)
France
UK
US
Germany
Luxembourg
Netherlands
Spain (mainland and Mallorca)
Greece
Sweden
Italy
Croatia
Switzerland
Turkey

My favorites were probably Italy and Greece. Greece was actually a sort of school trip in my last year of high school. I was drunk or high half of the time, did pretty crazy stuff. I wouldn't want every vacation to be like this, I'd probably be dead by now, but it was fun for once.