3. Superman/Batman
The suggestion of that title - Superman VERSUS Batman - rather than "And" or a helpful, but difficult to pronounce forward-slash is that the two superheroes will be forced to face off at some point in the film. Clearly, the smartest reference point - and the one everyone seems to be talking about with the most gusto - is that of The Dark Knight Returns, in which Superman arrests an old man Bats, at the behest of the President, and the two square off, with Batman beating seven shades out of the spandex wearing alien. This is likely to happen in some form, with Superman cajouled into taking down Batman by a trickster villain (the smart money would be on Lex Luthor) rather than Reagan, at least until the pair realise they should be united under a common enemy or something. Or of course they could go with the Dark Knight Returns ending, as many suspect will happen, and Batman could pretend to die using chemicals, before he reappears just before the credits to reveal all. Unless something like that had literally JUST happened...
Why They'd Suck The problem here is that the greatest Superman vs Batman story is The Dark Knight Returns, and any messing with Frank Miller's classic would be intolerable, just as any other approach would be held up against it, and inevitably pale in comparison. And then of course there's the fact that the addition of Batman was clearly designed as a marketing boost for Man Of Steel, because of the original's perceived failure, and there's only one way a direct face-off will end in terms of popularity. Because of the respective states of each property, Batman would have an army of fans behind him, while Superman will have an enthusiastic core, and handing Supes a perceived victory would be foolish at best.