Softimage|XSI was the prefered choice at ILM for a lot of shots in StarWars, along with Maya for modelling, and a hell of a lot of in-house written tools to aid in their production pipeline.

What I mean by this is that big companies like those don´t go with ONE software only, they prefer focusing applets to tasks they do best. Hell, even we do it, when we use Maya, Photoshop and even AfterEffects to aid in the production of our creations.