Some of the old 80's horror like Elm Street is cool to watch in this modern era - I have no idea why I was scared all that time ago when I first saw it.
The worst horror movie I saw was Last House on the Left (Wes Craven's first flick) - was banned in Australia for a long time. When it was re-classified as R, I hire a copy to watch it. Terrible movie, but so bad you need to see it to believe....
Went through the whole porno stage when I was younger (as in watching them) but I don't watch them anymore - I think they can seriously sicken the mind (and my wife is not a fan either), then again I guess you can argue the same with horror movies....