This is my current favorite spooky "Gotcha" scene, only the movie hasn't been release yet.
It's from a movie trailer for "The Woman in Black," starring Daniel Radcliffe (yeah, Harry Potter is growing up). They've put out a bunch of previews, but the one that got me was a fairly short teaser. And at the end of it, Daniel is looking out a window at the marsh that surrounds this haunted house. And then the "gotcha" happens. It's quick and its creepy.
I've seen the play. Spooky stuff. And the movie seems to capture the haunted atmosphere pretty well. It opens early in 2012.