Thanks for the link, it was helpful.
I'm shopping for a new computer, and wanted to see if it was worthwhile to get SCSI devices. Although it won't be used as a server, I wouldn't mind the added I/O speed. It's probably not worth the extra cost, though.
From reading that article, it sounds like the main reason that it costs more to have SCSI I/O is not so much due to SCSI being intrinsically more expensive than IDE, but rather supply and demand. The peripheral manufacturers figure that people who want SCSI also want top-of-the-line devices, so they don't bother making their moderately priced equipment SCSI-compatible.