Wonders and blunders: what makes a great museum?

What makes a museum building successful? Until the arrival of Frank Gehrys Guggenheim in Bilbao in 1997, this question might have been almost exclusively focused on the best environments in which to view art. But the Guggenheims phenomenal success, which allowed the Basque government to recoup the construction costs within three years, moved the debate on to issues of branding and statement architecture.
Now the discussion has moved on again. In the public imagination, museums have been transfo