The first ones that came to my mind were "To Kill a Mockingbird" and "Gentlman's Agreement". Both starring Gregory Peck and both dealing with prejudice.

Apocalyose now
One Flew Over the Cuckoo's Nest
Sling Blade
American Beauty

(depending on the age of these hypothetical children)
Native Son
Glory
Philadelphia

Oh my god, Stand By Me, can't believe I almost forgot that. THE quintessential coming of age movie.