Thanks for the recommendations Jason & Ytrog!
Oh, I definitely wouldn't 'recommend' this movie, as it's not something many people would probably enjoy or even be able to appreciate. I simply was surprised by how much I admired it considering the subject matter.
The underlying themes and the way Pasolini crafted this film are quite extraordinary, in my opinion. Unfortunately, many of these will not be obvious unless you have some familiarity with things like the historical context (i.e., de Sade's novel being placed in fascist Italy), Pasolini's views and criticisms as a leftist intellectual regarding fascism and bourgeois society (e.g., the shit-banquet was essentially a grotesque and vivid commentary on the processed food industry), and film theory (e.g., if you don't really pay attention to how the final scenes are constructed, you'd never probably notice how it places you, the viewer, into the position of the four libertines, and what this implies).
If you choose to watch it, do so at your own discretion. It's definitely not for the faint of heart.