Windows [hopfully] XP. I'll try the dual booting thing with Linux if I can.

It will be an organic PC with self learning capabilities and automated connectivity to everything. The whole PC does not have ports, rather, you only need to "plug" (probe) the cable into anywhere on the organic PC's body, and it will just wrap around it and create the electric wiring needed. Its intelligence will let it decide what you plugged into it, and, if it couldn't, you can just tell it verbally - it is organic after all!

Mac Pro... eventually.
Need to upgrade from my 5th Gen 20" iMac. *pats affectionately*

Windows!

Windows PC. Going with the safe and old set, I might try the other ones when I have time to find something new.

Teh Linux workstation, please.

Everything I guess.
One rig (not Apple for the time being) with Windows + Linux, and if I manage to lay my hands onto a Mac copy than also that...

Windows of course

Macbook Pro looks nice.