Newsarama has a good first interview with Grant Morrison discussing the best Superman story in many years, All Star Superman:
I’ve told this story in more detail elsewhere but basically, we were trying to figure out how to “reboot” Superman without splitting up his marriage to Lois, which seemed like a cop–out. It was the beginning of the conversations which ultimately led to Superman Now, with Dan and I restlessly pacing around trying to figure out a new way into the character of Superman and coming up short...
Until we looked up to see a guy dressed as Superman crossing the train tracks. Not just any skinny convention guy in an ill–fitting suit, this guy actually looked like Superman. It was too good a moment to let pass, so I ran over to him, told him what we’d been trying to do and asked if he wouldn’t mind indulging us by answering some questions about Superman, which he did...in the persona and voice of Superman!
We talked for an hour and a half and he walked off into the night with his friend (no, it wasn’t Jimmy Olsen, sadly). I sat up the rest of the night, scribbling page after page of Superman notes as the sun came up over the naval yards.
My entire approach to Superman had come from the way that guy had been sitting; so easy, so confident, as if, invulnerable to all physical harm, he could relax completely and be spontaneous and warm. That pose, sitting hunched on the bollard, with one knee up, the cape just hanging there, talking to us seemed to me to be the opposite of the clenched, muscle-bound look the character sometimes sports and that was the key to Superman for me.