My home PCs have gone from Pentium 200MMX (+SCSI) to Athlon 700 to Athlon XP 2100+ (1733MHz).
By my reckoning, my next PC should be badged as a "6300" (whatever that means, oh and Intel are dropping such a naming convention). Whatever, what I really want is x86_64 (Athlon 64) and HyperThreading (Pentium 4/Xeon). Will that ever be available? Who knows.
As for disks, I still can't warrant the expense (or noise) of decent SCSI disks (let alone FC-AL ;-). I hope SATA is running at 200 or better by then.