TDT 3D has put together a comparison of six 3D modeling tools. I am not going to get too deeply into the finer points of the products and what the TDT 3D reviewer thought of them, but many readers got quite worked up about one of the tools, Blender 3D 2.45.
What was the problem? Certainly not the price. Blender is a free, open-source tool that is compatible with all major desktop operating systems and even a few relatively obscure OSes -- Solaris, FreeBSD, and Irix. The features also got high marks. The reviewer gave Blender props for UV tools (a 3D texture-mapping technique) and fluid simulation, among others.
http://www.computerworld.com/blogs/node/6286