Snow White's certainly overrated; I mean it was the first animated feature film and does deserve a lot of praise for its artistic innovation, but too many people confuse first with best. Cinderella's pretty bland. I must disagree on Beauty and the Beast, though; as one of Disney's only movies to have three interesting, multi-dimensional lead characters, it gets a lot of props in my book (beyond the unfortunate abusive relationship/Stockholm Syndrome implications in the whole storyline).
It started as a cash-in, but it was done amazingly well. The "When She Loved Me" scene alone justifies it as adding new layers to the story. The movie's at least as funny as the original and several times more tear-jerking.
Oh, I'm pretty sure a lot of people were crying over Mufasa. I'd say Toy Story 3 hitting so hard emotionally is that it hits multiple targets at once. It's intense for kids fearing for their favorite characters, teenagers who are dealing with saying goodbye to childhood, parents trying to say goodbye to their kids, and religious/philosophical types connecting with the questions of if the universe cares and how to face a universe that treats people disposably.
As for movies I'd list as overrated, the whole Disney canon, though many of the films are good and a few are great, gets a bit overblown by people's nostalgia. Totoro's another film I'd count as great but overrated; it's fun and magical and observant like all of Miyazaki's other films, but Miyazaki's other films have more interesting stories so Totoro being considered one of his masterpieces eludes me. Wings of Honneamise is obscurer but by those who have seen it it's extremely overrated, moreso than those previous examples because I don't count it as good; I don't get how people can forgive the "rape is just a Big Lipped Alligator Moment" scenes and enjoy the movie.