Everyone uses a different 3D prgram... well, there are groups of people who use 1 same program of course...
my reccomendation... find some information online regarding the 3D sotware... here's an example :
3D studion Max 5 (or 6),
compare their functions...and decide which one you want to buy... to be frank with you, I use Max 4.2 myself, and I can tell you that making images or specific designs depends on how well an artist knows his/hers program
so basically, each of those 3D programs is more than capable for just about anything you want it to do