What could be the most optimised computer for postgres?

Hello every body,

I would like to know what could be the best computer for postgres?

I think a lot of memory is needed, but what about the disks, the
processors, etc...

I have actualy 6 SCSII disks linked with a raid 5 controler.
But I have a little processor (AMD K6 233MHz), and a standard
mother-board (ASSUS).
I will buy a new mother-board and processor(s), and I don't know if is
better to take some small processors, but 2 or 4; or just one very big
processor (like PII-450Mhz).

J�r�me Kn�bl