The Langholmen hotel used to be the largest prison in the country, but today the old cells have been renovated with Swedish minimalist modern design, and all the comforts a guest could want. The central courtyard where prisoners once walked has been covered with glass, letting in light but protecting against the cold. The hotel became operational 15 years after the prison closed. All rooms have a private bathroom and TV, and the cafe offers a simple menu at decent prices. Prices may seem expensive at first glance, but for Stockholm, it's really not bad. A single room is between 100 and 150 euros, a double between 140 and 180, depending on whether you're staying on a weekday or at the weekend. In summer there are special prices, and a part of the complex is dedicated as a youth hostel, so it's cheaper, but you'll share your "cell" with more people. There's free internet, breakfast is included, and it's in the middle of a park. The location is central enough to explore the island on foot, by bike or bus, and boat.
This is a real landmark hotel in the city of Stockholm. You have the chance to sleep on a boat in the centre of the city. There are cabins for up to 6 or 8 people, and are ideal for group travel. An affordable price for a unique experience. Don't expect luxury: you'll have to make the bed yourself, and the toilet is shared. But the boat has been renovated, and standards are good.