What would you consider to be some classic films/movies?

An example could be The Wizard of Oz, but what are some others?

Based on this criteria, or something along the lines of it:
~famous quotes i.e. “lions and tigers and bears, oh my!”
~good acting
~award winner (but doesn’t have to be)
~timeless
~something you could relate to
~appeals to any age
~has a theme

also, what do you think of these as being “classics?”
~Grease
~any old Disney movie