First I had mirrored 80 gig hard drives, then it became a mirrored 120 GB pair, when that ran out of space I tossed another 120 in and made it 3 in raid 5. When I had filled that I moved to twin 320 GB mirror, then one failed so I bought a 500 GB. That has morphed into 3 500 GB in raid 5 and 3 320 GB disks, 1 for backup and the other 2 mirrored.
I am now looking at 1tb hard disks wondering if I should continue buying 500 GB hard disks at $69 or start buying 1TB disks for $129