If you wanna go really crazy and find out the ultra ultra best way, without looking at money you could try something like this:
4 x AMD Opteron 8xx dual core processors (giving you 8 cpus)
4 x the latest GeForce graphics cards in dual SLI mode.
This would allow you to connect 8 monitors.
4 x 4 x 2 gigs of ram = 32 gigs of ram.
as mana SCSI harddisks as you can fit (I would think about 8) of the biggest size.
Audo cards, I'm not even going there.
I'm not touching the software part either.
Be prepared for a set back of around 20.000 dollars, give or take a quid (guessing).