Gone With the Wind. I've watched it many a time, and I notice something new each time. The cast is great, but it's really Vivian Leigh's film.
For some great behind the scene pictures, check this out:
http://www.tcm.com/tcmdb/title/414427/Gone-With-the-Wind/tcm-archives.html#tcmarcp-281824
If you like what you see, go to the TCM archives for more! Publicity photos, production photos, etc.
http://www.tcm.com/tcmdb/title/414427/Gone-With-the-Wind/tcm-archives.html#
In celebration of this movie (and those who worked on it), check out the following books:

http://www.amazon.com/Cukor-Gavin-Lambert/dp/0847822974/ref=sr_1_5?ie=UTF8&qid=1302825838&sr=8-5
Known as a woman's director, Cukor helped several actresses achieve some of their most well-known performances: Judy Garland in a Star is Born, Vivian Leigh in Gone with the Wind, and Katharine Hepburn in The Philadelphia Story. Gone with the Wind factoid: Cukor worked on the film for a long time beginning in pre-production, but he was removed early on due to creative difference with David O. Selznick, the film's producer. Main actresses Leigh and Olivia de Haviland were devastated by the decision, and they continued to see Cukor for guidance during filming even after his removal. Talk about loyalty!

http://www.amazon.com/Frankly-My-Dear-Revisited-America/dp/0300164378/ref=sr_1_2?ie=UTF8&qid=1302826366&sr=8-2
Normally I like to read almost encyclopedic works on film, but this was my first foray into actual film criticisms and analysis. Molly Haskell writes an interesting feminist take on Margaret Mitchell's literary classic.