I don't know from where you are but in India "Taare Zameen Pe" is a nice movie with strong social message.
this is my favorite : 1.To Kill a Mockingbird (racism), 2.Strangers in Good Company (courage, bonding, friendship, aging), 3.Rain Man (autism),4. Miracle (team work )
I like strong social messages move - Today i watched India's 2011 Oscar nominated movie "Adaminte Makan Abu". This film provide good social messages in INDIA.
12 Angry Men - the justice system 127 Hours - the human spirit, will to live I think both are good movie to learn lesson about life.