I don't know they are all in 3D which really can be hard to predict. I want to say HP but it always seems to be edge out WW by some film.
To the people saying Cars 2. Cars sucked balls. It is the worst Pixar movie by far. The gross was good and the merchandising revenue is ridiculous. I personally will not see it but a ton of snot nosed little kids will.
http://www.youtube.com/watch?v=F1gWECYYOSo
Please Watch/Share this video so it gets shown in Hollywood.