Demonic possession themed horror movies have always managed to unsettle me which is saying a lot since I've been watching horror movies for over forty years and found only a handful really able to put any kind of scare into me. The "Amityville horror" films are all based on a purported real life haunted house and the malevolent, often vicious spirits within this house that have driven its various occupants insane and even compelled them to murder and other mayhem.
In The Amityville Horror, and without giving too many details away for those who haven't seen this film, the "Lutz" family(George & Kathy, played by James Brolin and Margot Kidder, respectively and their kids), move into a house in Amityville(Long Island). Shortly upon moving in all hell literally breaks loose on the family and these terrifying occurences that occur inside the house prompt the Lutz family to flee the house in terror, all after only a single month living inside the home!
The first installment in the trilogy, 1979's THE AMITYVILLE HORROR, is my sentimental favorite although the overall special effects in the 1982 prequel are more entertaining to watch. Here's an HD trailer:
The Amityville Horror Trilogy Blu Ray set is available at Shout Factory's website and also at Amazon. To see this BD set for sale at Amazon click the link: AMITYVILLE HORROR TRILOGY BLU RAY set
Amazon also sells all three(3) of the films as a DVD set as well with a bonus fourth disc included: AMITYVILLE HORROR DVD set