It depends what you are looking for. If you want a movie to talk to you about the interventions and over-medicalization of birth in Western society then The Business of Being Born and Born in the USA are both good films. If you are looking for information on birthing naturally and want encouragement for your birth, I would look for videos of natural births and movies like gentle birth choices. If you have a doula or midwife they usually have a large lending library with all sorts of books and movies. My midwife let me borrow the video of her second child's birth and it was really beautiful.
We watched "Orgasmic birth" in my Bradley class. Don't let the title fool you, it's really just about low intervention birth. It's really inspiring. Not sure where you could find it, it's a fairly recent movie.
Re: Natural Birth DVD recs