My go to recommendation for people looking for something new is The Changeling from 1980 starring George C Scott. I recently showed it to a bunch of Film Grads, in a small theatre with a great sound system, no one had ever seen it. All came away liking it. It isn't a gore/Horror movie more of a Psychological Horror I guess? It is also a Canadian production, so generally a rare watch it seems. A great sound system helps as there are a lot of audio cues as well as visual.