POW awarded it the greatest moment in comic book history, with the author stating that his only reservation was that it was a new moment (in the late 2000's) out of a medium that's been around for 80 plus years. The author also stated that it was the only choice to make.
The end of the issue, as the Kandorians have failed to save him, Superman says it doesn't matter and they'll do much better working with human cells, so he goes to the children's hospital and tells the kids he's got some friends for them to meet and they'll be going home soon.
Jimmy: Don't let anyone see him like this! You hear me?
A small moment, but when Clark Kent is lying on the floor of the Daily Planet, seemingly dead, Lex Luthor arrives and begins to threaten the occupants. While everyone else is standing up to Lex, Steve Lombard, a Jerk Jock sports writer who spent all his time bullying Clark is kneeling by him performing CPR.
Steve: Come on, Clark! You can do it, buddy! Come on! ... I'm sorry for all those times I played tricks on you...
The moment when the Kryptonian astronauts are lying, dying while Superman works through his options for saving them. They acknowledge the nobility Superman shows in trying to save two people who had spent the entire issue savaging everything he stands for and trying to beat him into submission. Superman points out he learned of mercy from his human parents.
In Issue 10, Superman creates an alternate Earth in a miniature universe so he can find out if a world could exist without a Superman. Even in Earth-Q, the sped-up history shows humanity at various stages of enlightenment championing the concept of a Superman. Leading up a moment that's one millisecond away in reality where a young man in Earth-Q's Cleveland is putting pencil to paper: