Several things seem clear from the start:
- One GPU won't do the trick - I'll need CrossfireX or SLI.
- Given the potential performance gains, I'm gonna wanna overclock.
- With (overclocked) high-end CPU and GPU(s) generating more and more heat, watercooling will be necessary sooner or later. In fact, for a rig of the scale that this one is likely to grow to, it will have to be a fairly beefy watercooling rig at that.
- I'm going to need a big, well-designed case, with enough room for several foot-long PCIe boards.