Belgrade, Serbia: Cheap, modern, river views.
Cheap? Check. Meet some cool people from all over the world? Check. Nice views? Nah, that's just not a selling point for most hostels.
At ArkaBarka in Belgrade, Serbia, its location on the Danube really does set it apart. Permanently floating at the water's edge in the city's main park, you'll get million-dollar views for $20-40 a night in clean, modern rooms, free breakfast and internet. The cafe area on the ground floor is used for various musical and art events as well as parties. It's a 20-minute walk from the city center (or a short bus ride) but there are also bars and restaurants close by.
This is one hostel that you wouldn't mind having as your own riverfront property.