I recently updgraded from the 8600 GTS to the EVGA 640 MB 8800 GTS and use it with LightWave 9.3.1, Deep Paint 3D, ZBrush 3.1 and Poser 7. Also, I have the Max 2008 demo and the Maya PLE. I can say that it works most excellent with those programs. Also, there are a great many pros using that card as opposed to the Quadros. You can Google the subject and find that advice all over the 'net, in 3D forums around the world.
I was going to get a Quadro, but was talked out of it in the same way, with the same arguments being delivered here.
Alot of these people also model for games, and need the ability the 8800 has in gaming in addition to its ability to work with the OGL and DX programs.