Blender for modeling, animation, etc. And Unreal Engine for game development and real-time visualization.
Slightly specialized I know, but I thought Randy Heit did great work on the ZDoom engine. Jaakko Keränen also did some really good things with the Doomsday Engine.
Blender. Note: you really need a 3 button mouse. I spent hours trying to figure out how to use this program, before you could find hundreds of videos online, and kept failing. Aside from that, it works really well.