Personally, I think that everyone needs to calm down about this. For a few reasons.
Reason #1: Man of Steel actually wasn't that bad of a movie. In fact, I think it's one of the best comic book adaptations I've seen in a while, when you consider the fact that a majority of the inspiration for that movie came from the 1986 Post-Crisis version of Superman, whereas the original Christopher Reeve/Richard Donner movie (and the sequels that followed and Superman Returns to a point) were based on Pre-Crisis Silver Age Superman. Man of Steel wasn't a Michael Bay style all-style, no substance sort of movie. It had substance and heart, it was just a different Superman that audiences who don't read the comics weren't used to seeing. Also, to those of you complaining about what Superman did to General Zod at the end of Man of Steel, in Superman Volume 2, Issue #22 Superman did much worse to Zod when he didn't just kill Zod, he executed Zod, and his army. Zod in Man of Steel got a much less brutal death, at least Superman in that movie tried to give him a chance to surrender before he snapped Zod's neck in order to save that family. Plus, there was really no other way out, Zod was a rabid dog, there was no prison on Earth that would have been able to hold him, and the Phantom Zone was closed with no way to re-open it. And to those who still complain that Superman didn't care about saving people in that movie, bull, he saved those people on the oil rig, he saved that Air Force helicopter gunman that fell out of his helicopter during Zod's attack on Smallville, he saved his mother, and he RISKED HIS LIFE TO DESTROY A MACHINE THAT WOULD HAVE KILLED EVERYONE ON EARTH! Now, most people will try to counter this argument by saying that he didn't try to save anyone in Metropolis when he was fighting Zod at the end, to which I point out a few things. One, he saved that aforementioned family from becoming barbecued by Zod's heat vision. Two, Metropolis had been mostly evacuated, and there were no people in those buildings that Superman was knocking Zod into. Three, he did try to move the fight away from Metropolis when he knocked Zod into space, but Zod knocked him back down to Earth, since Zod wanted the battle to remain in Metropolis. Four, if there were any civilians caught in the crossfire, if Superman had tried to take attention away from Zod in order to save them, Zod would have taken advantage of that to either whup Superman some more, or to kill more civilians. Five, Superman was very green and unexperienced in this movie, whereas Zod and his army had military training.
Now, that I have said my two cents on Man of Steel, a movie I have enjoyed and consider to be the best Superman movie since the 1978 Richard Donner film, onto Ben Affleck as Batman.
Reason #2: Okay, I will admit, when I first heard that Ben Affleck was going to play Batman, I was a little bit skeptical. I am not an Affleck hater, as I have always considered him to be an underrated actor, even during that period ten years ago when it was popular to hate him and anything that he was in. I'm one of the few people who thinks that Daredevil actually wasn't that bad of an adaptation, yes it had problems, but Ben Affleck was by far the least of them. I have yet to see the Mark Steven Johnson Director's Cut, but I have been told that it is a vast improvement over the theatrical version. However, after giving it a lot of thought, I'm actually sold by the idea.
First of all, I don't think there has actually been an actor who has portrayed the definitive Batman yet on film. Michael Keaton was a good Batman, but he wasn't the best Bruce Wayne, whereas Christian Bale was a good Bruce Wayne, but should have done better as Batman in retrospect. Especially with that voice he did in The Dark Knight Trilogy that everyone has made fun of. (Don't deny it, come on, everyone has made a Christian Bale Batman voice joke, or at least tried their best to do a humorous impression of it.) We might actually with Affleck get an actor who can play both roles well. And before you say that Affleck is a bad actor, he has had some very good performances over the years, his performances in Good Will Hunting and Argo, which he also directed, are examples of good performances from Affleck. (I have yet to see The Town, but I'm told that his performance in that is great as well.)
Second of all, a few months ago, I purchased the complete DVD boxset of Batman: The Animated Series, and after looking at the way that Bruce Wayne was drawn in that cartoon, he actually does have a Ben Affleck look to him. Seriously, do a side-by-side comparsion using Google Image Search, you'll see a lot of physical similarities. Besides, Ben Affleck is a Caucasian man with a strong chin (trying not to sound racist when I say that) so he already has the only true physical requirement to play Batman outside of physique, which he will no doubt work out a lot at the gym to achieve.
Third of all, when it comes to Batman in movies, casting has always had a habit of being controversial and yet working out for the better. Three good examples of this include the aforementiond Michael Keaton in Tim Burton's Batman and Batman Returns (I know I said he wasn't the best Bruce Wayne, but I more blame Tim Burton for not getting Bruce Wayne, not Keaton.), Heath Ledger as The Joker in The Dark Knight (seriously, does anybody remember how everyone complained about how that wasn't going to work and that Ledger would suck?) and last, but not least, Anne Hathaway as Selina Kyle/Catwoman in The Dark Knight Rises. (I still think, adaptation-wise, she's the best on-screen live-action Catwoman). That's a three-for-three record, so I'm not getting my britches in a buch about it, especially since we haven't seen any shots of Affleck as Batman or even seen a freaking trailer yet.
Fourth, and finally, Affleck has a lot of supporters besides me as him as Batman. So far, Adam West (Batman from the 1960's Batman TV show and the movie spin-off), Michael Keaton, Val Kilmer, and Christian Bale (George Clooney refused to comment on anything Batman, and can you really blame him? I mean, I think he could have made a good Batman if he was in a different type of movie than Batman and Robin ended up being.) have showed support for Affleck as Batman, as has Joseph Gordon-Levitt (Gordon-Levitt is my all-time favorite actor, but there is no way I would want to see him as Batman, though I would have loved to see a Nightwing spin-off from The Dark Knight Rises) and even big-time Hollywood comic book geeks Kevin Smith and Joss Whedon support Ben Affleck as Batman. (Smith and Whedon also loved Man of Steel as well, and have defended it from it's critics, being the big comic book nerds that they are.)
Seriously, I think that the majority of this thread is being unfair and prejudgmental. At least wait for a picture of Affleck as the Caped Crusader, or hell, a trailer, before you start judging. If Affleck is great and turns out to be the best on-film Batman to date, then everyone wins! We can get future DC movies and the Justice League movie. And if Affleck totally sucks, (which I think he won't) well, then guess what? The world will move on. Remember, there are a lot more pressing problems to deal with than "OMG OH NOOOOOOEZ! BEN AFFLECK IS GOING TO RUIN BATMAN!" in the world. (Need I remind you that the whole world is in debt, people still struggle to get a decent job, the government shutdown, and the things that happened in Egypt and Syria back when this news was first announced?)
Calm down, people, please!