Don't forget to at least check out 3dsmax at autodesk. It is a very powerful app that can do a lot of different types of 3D work.
It is expensive but comes stock with a lot of tools that are additional expense for many other mid or top end apps.
It is widely known as a very good modeller and has many modifiers (undoable for many layers). No app can twist a poly quite like Max.
Ships w. MentalRay renderer, Vue file renderer, and a default scanline renderer.
Might have more plug-ins available than any other application.
Has a relatively steep learning curve; but I like the interface a lot. The learning curve is steep because there are so many things it can do. For instance, it comes with 6 or 7 types of shaders: Phong, Blinn, Oren-Nayer-Blinn, Anisotropic, Strauss, Translucent, Metal. (and others available as free or cheap plug-ins) Each of those has MANY parameters that can be tweeked. Takes a while to learn what all those parameters do, and that is just shaders.

EDIT - Sorry Bryster, had to throw this post in there.

Friends don't let friends use booleans.