Recommended hardware for Linux/3D/rendering?

[Scott Ehrlich]

I have a client who is migrating from an SGI to Linux.   He does a LOT of
3D rendering from thousands of stacks of images.    I plan to propose at
least two configurations - a desktop configuration from an integrator,
such as Dell, and one using COTS parts.

What recommendations would you suggest for RAM, CPU, video card, and Linux
distro?   He is also a heavy OS X user but has a need for a souped-up
Linux box.   Budget is not an issue.

I will do my own research, too, and see where suggestions from this list,
along with my own research, lead.

Thanks!

Scott