Wow guys.. Come on, seriously, why sepnd so much on a HDD setup. Its insane. SCSI are only used for server usage and such. They deliver faster speed than the 10k raptors or the 7200 satas.. for about 600$ more..
You can get a nice raid setup with simple sata HDDs and perform jsut as good as having 1 15k SCSI. The main point of getting the scsi hdds is for the datatransfer of 320 mb/s compared to the 150 on satas. Windows doesnt even support that speed, so no use. Its mainly for servers, so it can spread the speed throughout many different pcs.
You guys probably wont be able to make a difference with scsi hdds at your level...
My current specs:
Biostar TPower x58
XFI GTX260 Black Edition
640 WD Caviar Black
Vista Home Premium x64