...is this one:
You've got flurries of dead leaves, creepy-looking trees, dim and weird lighting, and, of course, the excellent mood-setting music of Danny Elfman. You've got not-quite-straight camera angles that add to the discomfort. Keaton doesn't say a word, and that adds to the mystery. He turns on the map light to punctuate the point that he's not letting anyone get too close. He's the dark knight, not the approachable knight. In my opinion, nothing illustrates the whole Batman persona better than this scene.
I also liked Nicholson's Joker the best. He wasn't just crazy. He was willfully evil. He was truly a monster.
Which Batman movie is your favorite, and which scene is your favorite?