Depending on what kind of animations you want use it varies. I use several programs for many processes, I use photobucket or photoshop for pictures, animations, and any file similar to that, I use...
Monsters Vs. Aliens, Madagascar 2, Kung Fu Panda, Shrek 3, Bee Movie, Over The Hedge, Madagascar, Shark Tale, Shrek 2, Shrek, Antz and all of the Dreamworks Animation Movies.
Some for all movies....