To quote Several of Lila's...
Breakfast at Tiffany's
The Wizard of Oz
The Sound of Music
The Way We Were
Gone With the Wind
National Velvet
My Fair Lady


Then to grab a few from xc. . .
Fahreinheit 451
To Catch A Thief
Arsenic & Old Lace (we watched this in my english class in 8th grade, it was so hilarious, I saw it on AMC one day long ago and recorded it. I watch it all the time now.)
Dr. Zhivago
Casablanca


Let's see...I know some of these are already mentioned, but I can't remember by who.
Rear Window
A Streetcar Named Desire
2001 A Space Odyssey
Blade Runner This used to scare me so much when I was little, but I watched it all the timeThe War of the Worlds
The movie about Gypsy Rose....I can't remember the title right now..
Mary Poppins
When Worlds Collide
All Quiet On The Western Front


I'll think of more, these were all pulled from the rest of yours, because as i was reading them I'd be like "Oh yeah!" and so I put it up here.