This is something I have already begun implementing, but I have to figure out the best way for the massive storage of files and backups that are easy and cost efficient
I just finished building my G4 Powermac Media Server.
I have a MacPro but I didn't want to waste the CPU cycles and the power usage should be lower.
All told I'll have spent w/o drives maybe about $250 on the G4
That includes a G4 powerful enough for leopard, 6 internal sata ports, and a usb 2.0 card for it. I have it connected to my airport extreme via gigabit and it's headless and managed by my iMac, Mac Pro, or Macbook Pro from anywhere in the house via screen sharing.
I've got about 3 TB's of movies/tv shows, and then about 3 TB's for backups from my other macs
Its working like a champ so far and it's a beauty, I love the design of the old Quicksilvers.
I'm going to write up a big review for this on a new thread in the next couple of days. It's a great NAS and works well beside my other Macs.