Amsterdam can be pricey and I prefer Den Hague for buying weed from. I love the Dam and visited there almost every month when I lived in Holland (1987 to 1999) and it's got such a variety of attractions, definately my number 2 European city (Rotterdam #1).

Hostels are safe , the movie hostel was actualy based on a web advert that the writer of the movie supposedly found. The story goes that an advert on the web offered people the opportunity (for a price) to kill another human being with no consequences. I suppose it would be possible in under developed countries but it's hardly likely that you could just go round grabbing tourists out of hostels in Europe.