There has been widespread discussion of Superman as a Christ figure in the movie Superman Returns.
The humanity or non-humanity (i.e. divinity) of Jesus Christ was a hotly debated theological issue for hundreds of years, and is still not unanimous, with Unitarian Christians, for example, dissenting from the now orthodox view. We know a great deal more about whether Superman is, or is not, human. Superman Returns emphasizes the fact that he is not.
What does this mean? Theologically, it means that while the Superman story is a Gospel, it is a Gnostic Gospel, not an orthodox one.
Fortunately for Superman, however, most of the Christian conservatives who are praising this aspect of the movie lack the theological background to notice.
Incidentally, there would be a good case for arguing that if Spiderman is a Christ figure would be both human and non-human in a way in which the non-human part predominates, making the Gospel of Spiderman a Monophysite Gospel, and that Batman is a Christ figure, that his Gospel, as it involves someone completely human, would be a Arian, or Unitarian Gospel.