The following are/were extreme to me:
Cannibal Holocaust
Africa Addio
Last House on the Left
Last House on Dead End Street
Philosophy of a Knife
City of the Living Dead (my first 'nasty' experience)
Wet Wilderness
Gestapo's Last Orgy
The Last Victim
The Legend of Hell House (the 3 or 4 times I saw this on TV as a kid I could never get past the bit of the record player going on by itself. It used to spook the shit out of me.)
Edit: an honourable mention to the fantastic Singapore Sling.
