Things you will need:
1x Stainless Steel Box from Ikea (Emu
) - This actually comes in a set of two. I wanted something small, so I chose the use the 7x10 box, but the larger box will work just great.
1x Mini-ITX motherboard - The Mini-ITX form factor motherboard is really brilliant. Compact, powerful, low-power, and usually the processor is integrated right into the board, so you don't have to worry about anything. I'm using the Intl D945GCLF2
Hard drives - depending on how much storage you need, this will vary. I went with a 1.5TB Seagate Barracuda 7200.11. I'll warn you that this drive has a bad reputation for RAID setups, so if you're going to do something like that, make sure you get a drive that has a better track record.
Power Supply - The Pico PSU120. This is quite a bit of power in a little package, 120w to be precise. I love these things. There's no way you'll need more power than this thing can dole out.
A Fan - I had an 80mm fan from another project hanging around, and I realized that I'd probably need it if I didn't cut some vents in the top. My fan is extremely quiet. I'll warn you that the fan onboard the motherboard is not very quiet. DON'T TRY TO RUN WITHOUT IT. The video chipset will not survive with passive cooling.
Ram - 2GB, it's the max this board will take.
An ATX power-switch - This a little power switch to turn on and off.
2x Right angle mounting brackets. You'll use these to mount the Hard-drive.
Assortment of screws and nuts - 6-32 thread screws are the standard hard drive screw, and I found that those screws of different lengths worked great for everything. I did use 8-32 for a couple of things, but there was no difference practically speaking.
Cost for Project:
Kingston Ram 2GB: $22.99
Intel D945GCLF2: $83.99
Seagate Barracuda 7200.11 1.5TB: $129.99
Ikea "Emu" boxes: $6.00
PicoPSU 120 60W kit: $54.95
Various Screws, Mounting Hardware: ~$10.00
Total: ~$308 not including shipping. No doubt you could get a NAS for cheaper than this, but you won't get the expansion or flexibility.