I stumbled across Unraid while flipping through the AVS forum last night. Seems like a great idea for the price.
I ordered the parts today and can't wait to give it a try:
Asus P5PE-VM ------------------------------------------- $58 (Free Ship) at Newegg
Celeron D 3.2 Cedar Mill core ------------------------- $58 (Free Ship) at Newegg
Stacker (Blue) --------------------------------------------- $99 - $20 rebate + ship at SVC
(3)Seagate SATA II 400GB --------------------------- $99 each (free ship) at Newegg (bit of a pricing mistake this morning)
PROMISE SATA300 TX4 ------------------------------- $66 at Newegg
512MB Kingston PC3200 ------------------------------ Free, just sitting in the drawer
550W Thermaltake PS --------------------------------- Free, just sitting in a box
(3) Vantec MRK-200ST-BK SATA Racks ---------- $37 each Directron (didn't need them, but why not)
I'll give it a try with the free version and if it works well then I'll buy it and starting adding drives as I find deals!