Just ran across this article that describes how the CandyFab people slice their objects, using open source software no less. [
www.evilmadscientist.com]
I don't think that this is any better than what we've got already, but it's interesting to look at the alternatives (and you can make a killer rendering of your STL model!).
I've used POV-Ray before, and it's a very capable graphics editor if you're willing to get down into the nitty-gritty markup of it.
