Definitely Hunchback. I love how epic and dramatic its score is, and the songs work well to suit the story, even if they may not get stuck in your head like other Disney numbers. Other soundtracks I love are:
Cinderella
Alice in Wonderland
Sleeping Beauty
All of Alan Menkin's other Disney soundtracks (TLM, B&tB, Aladdin, Pocahontas, Hercules)
Toy Story
Monsters, Inc.
