"The King’s Speech"
See this film. It’s excellent. It’s about George VI’s struggles with stammering and his relationship with his speech therapist. But that sounds like a terrible idea for a movie, whereas in fact the film is excellent. I note that 2006′s The Queen was excellent as well, further bolstering the case for constitutional monarchy.
But should films really be limited to British monarchs? Of currently reigning sovereigns, Juan Carlos of Spain has had a much more interesting life than Queen Elizabeth, and of World War II-era monarchs, Wilhelmina of the Netherlands seems more noteworthy than George VI.