The Music Man
In the 1962 movie, Preston reprised his role as Harold Hill (this after Cary Grant turned it down).  It also had Shirley Jones as Marian, Buddy Hackett as Marcellus, Hermione Gingold as Eulalie, Paul Ford as Mayor Shinn, and Ron Howard as Winthrop.  The movie is very similar to the musical, except that it replaces the song "My White Knight" with "Being in Love".