There's a great piece of free software out there, which the creators are trying to make a standard, so I shall give them a great big (non-commercial) plug here.
The piece of software is called POV-Ray , and the latest version (to my uncertain knowledge) runs on pretty much any platform. And yes, before you Mac people ask, there IS a Mac version. For all you English people out there, here's a non-functional link to the fastest place I found to download all the files from. It'll be a proper link as soon as I can convince this browser to accept it as an address in it's own right. I've managed to do so, but I've still no idea why it didn't work before...
ftp://sunsite.doc.ic.ac.uk/Mirrors/ftp.povray.org/povray/Official-3.0/
Why do I want a ray-tracer at all? There is a reason. One of my other hobbies (I have many) is racing model cars, and I thought it might be fun to model racing cars. To this end, I spent many hours fruitlessly searching the web for a 3D modelling package, and being of the 'I can define shapes easier than draw them' school of thought, I eventually ended up with this.
There will be (as soon as I bring the pics into work) some samples of artwork here, but until then, you'll just have to take my word for it that they're great.
Presumably, you could go to
Abalon's Home
if you felt the need.