The answer to your question isn't all that simple for at least 3
1. Talent rather than tools matter most when it comes to animation
2. Some packages are stronger in some areas than others
3. People tend to be platform biased
So accept my take on this knowing that I prefer to work with SGIs/Macs.
The best program to learn 3D on that is both very affordable and capable
broadcast/film graphics (Men in Black, Babylon 5, etc.) is LIGHTWAVE.
It'll do most of what you may need be it effects or characters. You'll
be up and running in minutes and you won't outgrow it any time soon.
There's a version of it for almost any platform.
Here's a very basic list of 4 groups of packages beginning with consumer
products and ending with high-end workstation solutions. It's in no way
complete, but will give you a general idea. 3D Studio Max and Lightwave
have the largest following by far. Pick up 3D Design and/or CGW to learn
Strata Studio Pro
Electric Image & formZ
3D Studio Max