trueSpace was one of the first 3D applications I tried, way back in 2000. It was version 4 back then, and while its interface was a little different and it didn't have all of the state-of-the-art features, it was quite capable and got me through a few projects.
Now on version 7.6, trueSpace has quite a lot to offer, based on the features page. And to make that deal sweeter, it's completely free! Seems Microsoft purchased Caligari, the creators of trueSpace. I guess they want to compete with other free 3D apps, particularly Google SketchUp. Gee, I wonder why?
There's only a PC version, so Mac users are SOL in terms of trueSpace.