really depends on your budget, if you have lot of money, get a SCSI disk and if possible a SCSI RAID controller. but you can still make a decent system with RAID 0 (stripping) with a good 7200 rpm IDE disk with a good onboard RAID controller!
The Asus P5B266-E is a good board for such an application, or the Abit TH7-II-RAID if you plan on RDRAM. If you are going with a P-III system, the Asus TUSL2-RAID is a good choice, while for Athlon the A7A266-E or Iwill XP333-R (with RAID) is good one. It supports decent overclocking too!
A SCSI card or the RAID controller has its owm BIOS, you dont have to do anything to get it recognsed, just set the options in Boot sequence to SCSI first and you are done. After the OS is installed, you can now load the proper drivers that will get you the real performance!
girish