This page is a list of 3D modeling software for various purposes. I don't have experience in using them except dabbling in a few as toy and admire the technology.
Note: 3D modeling software are quite complex and diverse. For examples:
In other software, such as word processor, image editors, different ones are still pretty similar. You know one, and you know them all. But this is entirely different for 3D software. Each one will have completely different user interface and the ways you create models.
Part of the reason is the inherent complexity in 3D modeling. First of all, you have to understand basic analytic geometry: coordinates, perspectives, projections, polygons, …, and can get technical, such as nurbs, math equations, physics of light, game engines …. 3D modeling are also tied to animating 3D scenes, rendering, both are quite complex.
AutoCAD is a CAD (Computer Aided Design or Computer Aided Drafting) software application for 2D and 3D design and drafting.
AutoCAD LT is a lower cost version of AutoCAD with reduced capabilities first released in November 1993. amazon
AutoCAD Freestyle is a simplified, low-cost (US$149) application that makes it easy to create accurate, professional-looking 2D drawings and sketches. amazon
Autodesk 3ds Max
Autodesk 3ds Max, formerly 3D Studio MAX, is a modeling, animation and rendering package. It has modeling capabilities, a flexible plugin architecture. It's frequently used by video game developers, TV commercial studios and architectural visualization studios. It is also used for movie effects and movie pre-visualization.
In addition to its modeling and animation tools, the latest version of 3ds Max also features shaders (such as ambient occlusion and subsurface scattering), dynamic simulation, particle systems, radiosity, normal map creation and rendering, global illumination, a customizable user interface, and its own scripting language.
Autodesk Maya is a software application used for 3D animation, 3D modeling, simulation, visual effects, rendering, match moving, and compositing.
Maya is used in the film and TV industry, as well as for computer and video games, architectural visualization and design.
Autodesk Softimage is a 3D computer graphics application for producing 3D computer graphics, 3D modeling, and computer animation. The software is predominantly used in the film, video game and advertising industries for creating computer generated characters, objects, and environments.
Zbrush is a digital sculpting tool that combines 3D/2.5D modeling, texturing and painting. It uses a proprietary "pixol" technology (see below) which stores lighting, color, material, and depth information for all objects on the screen. The main difference between ZBrush and more traditional modeling packages is that it is more akin to sculpting. amazon
Mudbox is a computer-based 3D sculpting tool, akin to Zbrush. Mudbox was created by Skymatter, founded by former artists of Weta Digital, where it was first used to produce the 2005 Peter Jackson remake of King Kong. With a simplified interface to allow for a more intuitive experience, Mudbox's primary application is high-res digital sculpting, displacement and normal map creation, though it's also used as a design tool. amazon
Second Life is a Virtual world. It is not much of a 3D molder, but more as a 3D virtual world environment where you can quickly build basic concepts of architecture or a 3D object, and immediately explore it inworld such as walk-thru or fly thru.
Second Life is not useful as a modeling tool for engineering, CAD, or creating pro quality animations. (you can, of course, make video recoding of the screen). Can't export to standard 3d formats.
To get a quick sense of what building is like in Second Life, see: Second Life 3D-Construction Tutorial. For video, see: second life building
The Second Life is completely built by its users. For more screenshots and videos, see Second Life Screenshot Gallery.
Discovered some new 3D tools:
Also, Unity (game engine) @ unity3d.com seems pretty hot.
Thanks to Wasamonkey and Pendle for corrections and additions.