[Phalanx]

The final scene in BATMAN: The Killing Joke definately deserves a mention...it's absolutely definitive in how the batman/joker relationship always has, and will play out.
After a no holds barred fight towards the end, the joker is beaten.
Batman tells him that he actually wants to get him well again, that the two of them are locked in on a suicide course with eachother, and that it doesn't have to end with them killing eachother, and that maybe he can help get his life back to whatever it was before he became the joker.

Smiling, but with tears in his eyes, Joker replies
"No, it's too late for that, far too late. Hahahaha, yknow it's funny, this situation reminds me of a joke...see there were these two guys in a lunatic asylum and one night, one night they decide they don't want to live in an aslyum anymore, they decide theyre going to escape!
So, like, they get up onto the roof, and there, just across this narrow gap, they see the rooftops of the town, stretching away in the moonlight, stretching away to freedom. The first guy jumps across without a problem, but the second guy is afraid to fall.
The first guy has an idea "hey, I have a flashlight with me, I'll shine it along the gap, and you can walk across the beam and join me!"
The second guy just shakes his head and says "what do you think I am, crazy? I'd get halfway across, and youd turn it off"

The book ends with both of them laughing as the police arrive to cart the joker away, the scene was just hugely definative, and kinda sad.