Ultimo Tango a Parigi
Last Tango in Paris

It's not strickly BDSM. but it does have the uncurrents of Domination and dependancy, and an amazing art film by one of the masters of cinema, Bernardo Bertolucci.

In case you can't tell, i just graduated film school. HAHA

AND i must say i'm a little surprised no one mentioned Secretary. (unless i just missed it) Very main stream movie, but deffinitly about love and domination.