Linux distro to use? Maybe Windows, too?

[MisterDNA]

I have a total of five working P4DPR Xeon nodes and three of the HDAMA
Opteron nodes now.

I want to run the machine as a Blender renderfarm under Linux, but
also as a UDK Swarm under Windows when needed.

I don't know what Linux distro to use other than the enterprise
versions being way out of my reach. I have plenty of Windows XP Pro
licenses.

I've looked at Coreboot and such, but haven't gotten a lot of info on
how to make a cluster I can switch on demand. It almost seems as
though it would be easier to just go to a factory BIOS on each node
and use a CF card in an IDE adapter to load the basic OS data in
either case.