Where do I begin?
1) I remember watching Phantom of the Paradise on TV when I was about five or six years old. It left me slightly confused and creeped out. I actually love that movie now. It's funny and cheezy at the same time.
2) Carrie. Saw that when I was about seven years old. The music, the blood, the hand popping out of the grave at the end. My twin used to threaten that the "hand" was going to get me. Yep. She did that for at least five or six years.
3) Amityville Horror. I was afraid to look at crucifixes and rocking chairs for a looong time.
4) I remember the nanny committing suicide by hanging when I watched The Omen on TV. Again, I was only a child. (My older sisters watched these movies in front of us.)
5) The Exorcist. I think I was about eight years old. Part I & II. Just bits and pieces of the movie I remember watching. I was afraid to go up the stairs and look at the white door that led to the bathroom because the door reminded me of the girl's bedroom.
There's probably more but those movies above stick out of my mind the most.