The Thing (1982) Director: John Carpenter Starring: Kurt Russell, Keith David, Wilfrid Brimley, Richard Dysart
John Carpenter's best film, The Thing is the ultimate counter-argument to the theory that you should never remake great films. Carpenter idolises Christian Nyby's (really, Howard Hawks') Arctic-set The Thing From Another World, but it still didn't stop him saying, 'you know what? This needs more gore, more ground-breaking effects, more paranoia, and more beards'. And he was right. Sure, it's a showcase for Rob Bottin's astonishingly freaky practical effects, but it's Carpenter who's the star, maintaining tension throughout (the blood-test scene springs to mind), even when the gore comes to the fore.
One Flew Over The Cuckoo's Nest (1975) Director: Milos Forman Starring: Jack Nicholson, Louise Fletcher, William Redfield, Will Sampson, Brad Dourif
Eighteen-rated movies don't have to be violent, horrific or full of language that would make Mary Whitehouse do backflips in her grave. Sometimes the most adult themes are those that make us look at the terrible things that people can do to each other without any physical violence. Milos Foreman's film of a crim (Jack Nicholson) who chooses to enter a mental institution over prison is in many ways a comedy, but the way in which the hospital eventually takes a perfectly sane man and turns him into a vegetable is, in it's own way, terrifying.