One of my favorite movies is "Grey Gardens" which is based on a real story.
In the 70's there was a documentary ( see the original trailer here: http://www.youtube.com/watch?v=AI62e0fRieo) made about two upperclass relatives to Jackie Kennedy, a mother and a her doughter, who ended up in real miserable decadence when they lost their money and sense. This movie is from 2009 and is inspired by that documentary. In the cast you see Jessica Lange as the mother and Drew Barrymore as the doughter.
For me, who love aristocratic decadence, this movie is so inspiring. Their way of dressing up is so cool if you see it with a fashion eye point of view and even though their story is very sad I get so fascinated by their fate.