Dan is right, the artists here use a WIDE range of tools. This is a sampling taken from environment, character and cinematic artists across the company.
Modo
3DS
Maya
3D Coat
Mari
Photoshop
Crazybump
XNormal
Knald
ZBrush
Sculptris
Substance Designer
WorldMachine
XnView
Sketchbook Pro
Storyboard Pro
Premier
Quicktime Pro
Motionbuilder
So … basically, everything. 
But the lesson isn’t to learn everything, it’s really to learn what makes you most productive. For example, learning modeling concepts in 3DS means you’ll be able to model in any app as long as you learn the new set of hot key and where all the menu items are. Skills are skills, and they don’t live or die in a specific app.