Not that I've read very many Superman stories, but my favorite is still Kingdom Come. The Lex Luthor in that continuity described his powers best when he said that Supes is like a solar battery, and with him living on Earth for so many years, nay, decades, absorbing all that energy, he was completely invunerable and nigh-omnipotent. It took the full strength of Shazam to just slow him down, and even after being weakened by that battle, he still survived a nuke that wiped out all (er, most) of the other meta-humans fighting around him. So this could be an accurate metaphor for Supes' status in the DCU as time goes by. Writers keep making him more and more powerful until a literal Crisis of Reality is needed to depower him (again). Tis a vicious cycle.
