This isn't a final page, but the most stunning page for a DC comic I can recall comes from Superman #149, which was reprinted in a recent Showcase volume. After luring him into a kryptonite trap, Lex Luthor kills Superman on page 16. The actual ending, which features Supergirl taking over for the dead Superman, ain't too shabby either.

It's an "imaginary" story, but still very powerful stuff. I would imagine that it was a major inspiration for Alan Moore's "Whatever Happened to the Man of Tomorrow?".