In the pre-title sequence, the close up on Craig's face after he finishes "drowning" his first kill. The camera holds on him for just the right amount of time (a little longer than you would expect, which only serves to give the shot more weight), then the cut back to Dryden saying "made you feel it, did he?" And Arnold's music, which is something I've never been a huge fan of, is just perfect here in this scene. It's very subtle, and it's not even a melody, it's more of a rhythmic device---but it's eerie, and it adds a sense of the foreboding to the proceedings. Just perfect!
Also, the way Campbell shot the pre-titles itself. The framing, the lighting, the angles, the look of the black and white, everything. It's too good to be true. The only complaint I have with it is I wish it was longer!