Perhaps the most disappointing thing with "scary" movies to me, is that most of them, at least the ones made today, have to do with supernatural creatures/events, and that just usually isn't where it's at for me. Sure, there are moments of the 'creepy' factor in certain movies with supernatural elements ("The Ring," "Paranormal Activity," "Exorcism of Emily Rose") but that's about it. Just a bit of the creep factor, rather than the actual scare these movies are meant to provoke.
The movies I find scary are things that could logically happen in day to day life, just out of the blue. The original "Halloween," the original "Black Christmas," heck, even the movie "Otis," it's logical, and entirely too real, for a seriously deranged, genuinely sick person to just show up out of the blue and kidnap, torture, and/or stab you to death. The idea of that skeeves me out more than any 'girl gets tossed into the wall by some invisible force that is haunting this and ONLY this house! OH NO! Clearly, the smartest and most logical thing here is to stay in said house until half of the family is dead. Oh, and scream lots. Musn't forget the screaming,' type of plot.