I figured you were pretty set on the Athlon XP. The only reason I suggested going to Athlon 64 is that if you will regret anything in 6-12 months it will be the software that is coming out to use a 64 bit architecture.
It depends on the SATA architecture. Many times the underlying controller configuration is still IDE, with a SATA interface layer added. Raid 0 will give you performance improvements on reading large amounts of data. Also there are big gains if the hardware is designed to do simultaneous reads. The mobo level Raid that I use is Raid 1 (mirroring) with 74GB Raptors.
For server performance, while SATA is interesting for network storage devices, Ultra320 SCSI with 5 or more drives is still the preference for most.
It depends on the SATA architecture. Many times the underlying controller configuration is still IDE, with a SATA interface layer added. Raid 0 will give you performance improvements on reading large amounts of data. Also there are big gains if the hardware is designed to do simultaneous reads. The mobo level Raid that I use is Raid 1 (mirroring) with 74GB Raptors.
For server performance, while SATA is interesting for network storage devices, Ultra320 SCSI with 5 or more drives is still the preference for most.