The Haunting with Julie Harris, Claire Bloom and Rus Tamblin.
The book on which the movie is based, Shirley Jackson's "The Haunting of Hill House," is even scarier than the movie.
One of my fave scary movies ---sometimes shown on PBS ----is "The Innocents" starring Deborah Kerr, set in a mid-Victorian English countryside estate, based on Henry James' book "Turn of the Screw."
I agree with you. The Haunting was one of the best. No major special effects, but it left everything to your imagination. The book "The Haunting of Hill House" which the movie was based on was even better.