One of the best R-rated movies ever was the original Robocop. It was not only incredibly violent, but actually had a great plot. The violence was so epic that they almost made it rated X. Now, since Hollywood doesn't have the ability to create an original thought, they are developing a remake.
The original movie spawned not only two additional sequels, but a cartoon and a television series. Stars such as Clive Owen and Hugh Laurie have been in talks to stars the a robot cop, but so far there hasn't been anyone named as star.