This is, potentially, the only movie I can think of that demands a 3D experience. Considering the storyline dives deeply into the tactics and strategies of conducting war in a 3D space rather than on fixed plane -- I really hope the film makers turn 3D into a useful storytelling attribute.
How does that fact that there is space war defeat all the arguments against 3D films? Namely, the fact that no one has ever had any problem determining depth from a "2D" projection, because parallax is not the primary source of depth perception in humans.
There are plenty of movies and television shows in 2D that feature air and space battles, and never once have I found myself thinking "Gee, I really wish I knew which of those objects was closer to me."
I said a 3D space, as in volume, not outter space. The story spends a great deal of time illustrating how Ender has a mind for assymetical battle, denial of ground, and other things prevelent to battle in zero G. Adding an increased or heightened awareness of dimensional depth to the film would be very valuable.
If I remember the book correctly, the 3D parts were actually games where the participants as people move around without gravity in 3D. In this particular case--much more than for an aerial battle with airplanes or space ships--I also think 3D would help with immersion.
Note: Im a pretty ardent 3D hater.