So I recently decided to start a "taboo" movie collection consisting of the most controversial films of all time. They're not necessarily great films, but they were banned at one time or another for their content, message, etc. I've always been fascinated with taboo movies not because of the movies themselves, but the controversy surrounding these films.  I'm kicking off my collection by purchasing Salo which is probably the most fucked up film I've ever seen (theres something genuinly evil about the movie). I was wondering if you guys could help me out and list other movies which I should check out. Thanks so much for your help!

This should help!

http://en.wikipedia.org/wiki/List_of_banned_films

Shortbus should be deemed a controversy since the opening scene features a guy blowing himself and it continues to some kind of all male orgy.

It got an R Rating here in Canada and I'd consider it porn since it has insertion.

I just saw Aftermath/Genesis which is a trilogy of three short films about death strung together as one. Aftermath is one of the sickest films I've ever seen. Surprisingly, the cinematography and sound are absolutely superb. No dialogue either so it's all told through visuals. Quality flick. I'm thinking about getting a copy myself.

If you can find some cheap copies of Nekromantik and Nekromantik II, those are must have's. Two of my favorite exploitation films although they're a little more artsy than most. Really, they only look like exploitation films. Very unique and the best soundtrack of ANY movie. The quality's not great though and the DVDs are extremely expensive for the most part. I'm still trying to track them down.

Blood Sucking Freaks is a given. Irreversible is as well.

And, of course, Salo is only one of three in the unholy trinity of sick and controversial movies. Caligula and Cannibal Holocaust are the other two. Caligula definitely sucks. I'm thinking about giving Cannibal Holocaust another shot but as far as I remember, it sucks too.

That said, Cannibal Holocaust spawned countless knockoffs, Cannibal Ferox being the most prominent.

You gotta do your research, buddy! Not all the controversial/taboo films are exploitation films. Some of them are full blown art films. Some of them share a little bit of both. A lot of them suck. You're gonna have to be choosy if you actually want quality (maybe quality isn't the word but good) flicks... that is, unless, you just want to own them all for bragging rights. That works too, I suppose.

Quoted from James McClung I'm thinking about giving Cannibal Holocaust another shot but as far as I remember, it sucks too.

The only controversy about Cannibal Holocaust is how much it sucked.  However, for some reason, I am also thinking of giving it another shot, maybe simply because of its notorious reputation.  I had such high hopes for this film and I was excited to see it, but man was this movie bad and god-awful.  Blah.

Salo I'd like to check out.  

Irreversible is the first film that comes to mind. Ken Park is another.

Ken Park... meh.

I went through a phase of acquiring banned films. I only tried to get the top rated 15 or so.

Some I liked (and hated with a passion because they were so sick) are:

Tras el cristal (In A Glass Cage) - fucked up.
Ai no corrida (In the Realm of the Senses) - probably the closest thing to porn, without being porn.
Xiang Gang qi an: Zhi qiang jian (Legal Rape)  - Funny at times, bit sick though.
Salo - obvious.
C'est arrivé près de chez vous (Man Bites Dog) - Very well made.
Bumfights  - Suppose it's on the list.
Run! Bitch! Run! - funny stuff.

All the others have been said. The top one I have is quite terrible. Watch it.

Well said James.