Games with built-in support for stereoscopic 3D displays are so 2010. Rocksteady Studios, the developer behind the upcoming Batman: Arkham City, understands this. That's why the October release isn't going to support one 3D display format.
It's going to support three instead.
Stereoscopic 3D is the format used for increasingly popular 3D-capable HDTVs, and many of the top-shelf game releases these days include support for it. The same is true of NVIDIA 3D Vision, another supported format that is exclusive to PCs.
The third 3D format in Arkham City is where things get interesting: anaglyphic 3D. The plus side to this one is that it works with any old TV. The tradeoff is that you'll need to wear a pair of red-and-blue-lensed glasses to take advantage of it.
Anaglyphic is the earliest 3D format, and as anyone who's experienced it knows, those glasses have a tendency to throw off the colors in the source. It might make for a fun novelty, but I'll wager that most non-3D TV (or Vision Tech) owners will opt to run through the majority of the game in regular, old 2D.