I've not been to Tallinn or Budapest but have been to Amsterdam numerous times. Aside from the easy eats/drinks/"bang for the buck", you could day trip Den Haag (sp.), Rotterdam, Zaandam, or Harlem (or Utrecht for more collegiate feel), let alone the fully opened Rijksmuseum, Anne Frank House (get a reservation), The Heineken Experience, river tours, Van Gogh museum, Vondelpark, the Sex Museum, Royal Palace etc. The multi-day pass on the light rail/tram (GVB?) is a good deal but Amsterdam proper is small enough to walk--especially for younger guys. From States you can also get there nonstop from JFK or EWR. My wife and I (and our friends) never worried/thought about crime in the touristy spots although like any big city, dumb tourists are always targets for petty crimes. I plan on returning as the hop off point for Groningen, Maastrict and Luxembourg. AMS is also fairly English friendly...