fastest workstation platform eh?
go for 2) if u want the fastest, but the most expensive...
dual p3 + DDR is the fastest right now for a workstation using smp capable software and OS...
get the dual p3 and MSI mobo using sdr for the next fastest system for considerably less money...
ddr memory is currently a GIANT rip-off...
if u wanna save a considerable amount of money and maintain excellent performance, a single proc athlon 1ghz+ on an Epox EP-8KTA3+ (whcih will be available early february - it's a socket A using KT133A chipset coupled w/ IDE RAID on board and multiplier adjustment, etc., plus stable fsb overclocking 150+mhz)
if u want a cheap scsi solution, the MSI master is a good choice...although it doesn't support DDR, so, for the fastest single proc workstation i'd suggest 4).
good luck