Copenhagen Admiral Hotel

Location, location, location

Word to the wise: Room choice matters here: if you can afford it, upgrade to a waterfront view.
Bang opposite the Opera House and a short stroll from Nyhavn, the Little Mermaid, Kongens Nytorv, and Strøget, the Admiral's location is unbeatable if you're in Copenhagen to 'do' the sights.

The hotel, a converted 19th century warehouse, is rather lovely, too. The building has retained a sense of history and character - rooms have their original beams - whilst furnishings follow contemporary Scandi design lines.
It's not cheap, and, in the past, service has left something to be desired, but the management now appear to have pulled their socks up.