it depends on what you want to do
free:
blender is probably the best. It is a studio (modeling, rendering, and animation)
For animation and games:
In the market place i would says 3dsmax, Maya are about equal. Then Softimage and lightwave. Then they are a ton of others that are really good. Such as: Modo looks very interesting and Zbrush have some great abilities for HQ models. Check out
http://forums.cgsociety.org/
If you talking about product development:
There is a lot, solidsworks, solidedge, unigraphics, autocad, rhino3d, pro/engineering... the list goes on
It really depends on what you want to do