Five3D

If you've had any dealings with Flash you probably know about Papervision3D - I'm a long way off being able to use it myself, but the 3D effects it produces are amazing.

Another 3D package that looks really fun is Five3D .  It's a vector based system that, judging by the examples,  can do some amazing stuff - especially with text.

Also, check out pixelwelders website for some really cool stuff - the opening page is all done with Five3D!