Rhinoceros a surface modeler is the least powerful but easy to use and it's probably the cheapest.
Alias also a surface modeler but a lot more powerful. Not as easy to use but you can get organic shapes fast. More expensive. Used more by movies I believe more than for products or cars.
Ashlar Vellum I don't know a lot about this one but it's used only on a mac I believe.
Solidworks a solid modeler it's very userfriendly while not losing it's powerfullness. I don't know it enough but I've seen organic stuff like cars done in this program.
Lightwave I think at first this program acts like illustrator and then after your finished working in 2d you can manipulate it for 3D modeling.
there are other programs like Pro E or Unigraphics but they get really pricy and are very hard to learn. They are very powerful though and they are used by industries like car manufactures.
