The scariest/creepiest one I've ever seen is ironically, a TV movie from 1991 called The Haunted, starring Jeffrey DeMunn and Sally Kirkland. It's based on a supposedly real life haunting of the Smurl family. I managed to find a DVD-R to purchase online a few years ago and it's the full uncut edition that has played on Fox Movie Channel. My second favorite would be Amityville II: The Possession from 1982. No other Amityville comes close to the creep factor of this one.
