This is one of my favorite lovely-melody numbers in all of the scores from the 1950's. I'm not usually as fond of Victor Young as other Golden-Age composers, but the music box piece always brings me up short - in the movie and on its own. And in case you're saying, "oh, no! a music box!" - it's not what you think at all.
Ah, yes—one of the loveliest pieces in all of film score history, especially the section beginning at 1:45. I have often thought that it should be expanded into a proper concert piece.