Classics I like, off the top of my head:
Psycho, In Cold Blood, The 39 Steps, The Third Man, Touch of Evil, Ninotchka, Ikiru, A Night to Remember (BTW I found all of these at my library, but wouldn't have looked many of them up if not for allmovietalk.com).
Someone mentioned Last Man on Earth, I haven't seen it but it's on Hulu
http://www.hulu.com/watch/46780/the-last-man-on-earth. While I was on Hulu I found another one I like..
http://www.hulu.com/watch/62386/a-funny-thing-happened-on-the-way-to-the-forumKids' movies I love: Dumbo, The Neverending Story, A Boy named Charlie Brown
http://www.youtube.com/watch?v=mGm6MICgeYM. Rewatching it now I realized how adult the dialogue was after only 30 seconds. Look out for the abstract Fantasia-like sequence near the end.