As a sidenote, if you do go RAID and join up 8 drives, it's well worth your while (assuming you have the cash and the stuff on there is important) to mirror as well as stripe, or if it's slightly less important, daily backup. I've seen more than one multi-drive array die well before it's supposed to ... I don't know what it is, but I think the disks know when they're very important and conspire to die in the most inconvenient manner possible. Many is the array I've seen last all of 3 months before a drive dies.
If you go that route, don't forget you'll need special case considerations. Space is no problem, as I've seen server cases with 10-12 internal 3.5 racks, but cooling is... you'll need air forced over each drive with an array of fans at the front, as any hot spot is going to get VERY hot, and stacking drives like that (with associated cables) does interesting things to your airflow.
Oh, and never, EVER use IBM DeathStar drives ;-)