5. 'Miracle on 34th Street' (1947)
Does the term "spoiler" apply when discussing a 63-year-old movie? Let's keep it a little vague just in case. Young Natalie Wood plays Susan, a little girl who's been raised to be logical and down-to-earth, so of course she doesn't believe in Santa Claus, even when Kris Kringle (Edmund Gwenn) comes to work at Macy's and convinces a whole lot of people that he's the real Saint Nick.
Suffice it to say that by the time Christmas rolls around, Susan's heart -- much like the Grinch's -- has grown three sizes.