[Bob Gray]

Here's a few I can think of.

1. The spider-walk scene in The Exorcist
2. The scene in The Shining when Jack sees the woman/corpse in room 237
3. The scene in Suspiria when Suzy Bannion enters a secret passageway to explore the witches' headquarters and is attacked by a reanimated, knife-wielding Sara.
4. The scene in The Blair Witch Project when the documentary crew gets attacked by an unseen force.
5. The scene in The Exorcism of Emily Rose when they are in the barn and Emily keeps chanting: "One, Two, Three, Four, Five, SIX!" over and over.
6. The scene in The Ring when the girl comes out of the tv.
7. The scene in the original The Haunting when Eleanor mistakenly believed she was holding the hand of roommate Theodora in the adjacent bed for comfort from mysterious and strange sounds surrounding their dark room.
8. The reoccurring nightmare scene in In the Mouth of Madness.
9. The alley scene in A Nightmare on Elm Street when Freddy's arms stretch out to disproportionate lengths.
10. The nightmare scene in Phantasm when Mike wakes up in the cemetery.
11. The scene in Salem's Lot of an undead, vampire boy floating outside of a bedroom window, while smiling and scratching at the glass and asking to come in.
12. The scene in The Texas Chainsaw Massacre when the sliding door opens up and there stands Leatherface.