I use almost any program that is closest to fullfilling the things I want...
But at first, I always open Jasc 7,
then Photoshop, Photodeluxe, GIMP, Koolmoves (flash development), etc. etc. to 3d cad, environment (terragen) etc.
The more programs you're using, the better the final result I think
(if you use them in a nice way, not just putting all the stuff together to get ChaoS:P)