I'm an oldie. Two of my all-time favorite scary/thriller movies were Rosemary's Baby and Psycho. I'm old enough to have seen both of them in the theatre and they were awesome!
I especially liked Rosemaary's Baby because it seems so incredibly plausible. The next door neighbor reminded me so much of a great-aunt of mine, I could easily see her in the role! It was a movie that didn't *try* to be scary, but the premise was quite believable. Acting, cinematography(sp), story... all 100% top notch.
And who can forget Psycho? I literally jumped in my seat at one point! Again, the acting and storyline were so believable. Alfred Hitchcock was a master storyweaver. Anyone remember Alfred Hitchcock Presents...? Superb!
These are two movies I can watch even now (actually, I did watch Rosemary's Baby just about 6 months ago), even knowing the outcome, and still get goosebumps. They have held up VERY well with time. Classics.

he will jump out from behind doors and stuff just to hear me scream or he will sneak up behind me while i am doing dishes or laundry.....grrr
out of me! Same part you are talking about!!!
I also liked Nightmare on Elm Street and It by Stephen King.
and all the witches heads