Films

Amazon.com DVD's and VHS
Amazon has become one of the most complete sources of hard to find movies and DVDs because of it's Marketplace program.

MoviesUnlimited
Looking for something really obscure? I would start here. MoviesUnlimited specializes in hard-to-find items.

MovieLink
Rent a movie online. It's the wave of the future. The only problem with this method is that it's only available to Windows users right now, which makes this Mac user very unhappy.