In response to Aethea's post....
I really don't think any deviation from the comics can be a factor in whether a comic book based film is a hit or not, especially when you are talking about really, really minor things like how his costume neckline is in comparison. The only people who care about that kind of stuff is Geekdom....I'm sorry to break it to you. Those several hundred thousand of us are NOTHING in comparison to the millions of average citizens who only know these characters from movies and TV. What does the average person know about Superman? They know the movies...they know Smallville, they know Lois & Clark. I mean, I haven't heard one single person outside of internet geekdom say they aren't seeing the movie because they didn't like the costume neckline. I mean...c'mon now. And Darkseid? Yeah, I love him....but NO ONE outside of geekdom knows who the F**K he is.
And about the movie Deviating from the DC Comics? Sure it does. But every single Superman adaptation has deviated somewhat...it's the nature of the beast. Also, when It comes to comic adaptations, the Tail ALWAYS wags the dog; The comics always pick up what the media adaptations change to the Mythos. When Superman: The Movie came out and hit big, not too many years later DC re-worked Superman to make him more like the movie cuz that's now what everyone knew as Superman ( For example: Krypton became a barren crytaline world, Clark was not Superboy in Smallville, etc. Even the Fan favorite "CEO Of LexCorp" Lex Luthor came about because Marv Wolfman and John Byrne, the guys who re-vamped Superman, liked the Gene Hackman Lex and wondered where a genius like him originally got all that money from. Even know, the changes brought about by Smallville in the Lex/Superman relationship are being reflected by the comics continuity. Like I said...the Tail Wags the Dog. So those of you who have seen Superman Returns should not be at all surprised if she makes a special announcment to Clark very, Very soon.
Now as for Wonder Woman, if Superman really does tank...then all bets are off. I could see Warners cancelling it outright frankly, which really would piss me off as I'm a huge Wonder Woman fan and a Huge Joss Whedon fan. Still, Warner HAS to not have nearly the same expectations for Wonder Woman. She's female character, and they have had notoriously bad luck in this genre. They probably hope it does as well as the first Charlie's Angels and Tomb Raider flicks, which each made around $130 Million or so. So it will have a FAR smaller budget than Batman and Superman, so it will be less of a risk.
If Superman Returns makes at least $200 Million, I think the other DC films will be safe, although they will have reduced budgets. But's it's not the money you spend, it's whatchya do with it. So what are you all waiting for?? Go see Superman again, and tell your friends to do the same...Dammit, I wanna see Wondy and Flash and The Watchmen and Green Lantern! ( Just NO Jack Black please! ) So anyways, that's my opinion.