"POVray, Yafray, 3Delight, Aqsis" Yup, been there, done that and have the scars to prove it. Throw in BMRT as well. Most of those guys can code raytracing algorithms in their sleep but build a decent GUI - that's left as an exercise for the reader I suppose. PoseRay is sweet. I might even learn a little of POV's language if it didn't take so long to see the results. Maybe when AMD starts giving away Opterons :-)

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken