Did anyone see the movie, "The God Who Wasn't There"? There's an interview with a gentleman named Robert Price who is a professor of Biblical Criticism. Here's a relevant quote:
"There are other similar savior figures in the same neighborhood at the same time in history: Mithras, Attis, Adonis, Osiris, Tammuz, and so forth, uh, and uh, nobody thinks these characters are anything but mythical. And their stories are so similar, most of them, in fact, having some kind of resurrection or another, um, sometimes even with celebrations after three days and so forth, that it just seems like special pleading to, uh, say, "Oh, well, in this one case, it really happened." The early church fathers understood that this was a problem, because they were already getting the same objections from pagans. They said, "What you say about Jesus, we've been saying about, you know, Dionysus and Hercules all the time, and what's the big deal?" And they didn't believe in them either, any more. And so the Christian apologists, the defenders of the faith, would say, "Well, yeah, but *this* one is true. Satan counterfeited it in advance 'cause he knew this day would come." Boy, I tell you, that tells you two things right there: That even *they* didn't deny that these other Jesus-like characters were before Jesus, or they never would have resorted to something like that. Satan knew it was going to happen and counterfeited it in advance?"
I can't find the specific quote but later he relates the mythologies to comic books. Paraphrasing: "Yea, we have SpiderMan, and X-Men, and the Green Lantern, and Captain America, but Superman? He's real!"