Homebrew NAS server questions

[Lord_Vyper]

I'm looking at making a NAS for my home network, to stream CDs/DVDs to both my computers, and my HTPC system.
Foxconn NF4PIK8AA Mobo
8x 256Mb ECC/Registered RAM sticks
Opteron 242 processor
8x 500Gb SATA II Hitatchi drives

(all snagged from work during a recent upgrade frenzy)

Now for the questions:
Any idea what size PSU I'd need for this? I'm guessing a good 500W? More?
What sort of cooling would this thing need? 2-3 120mm fans blowing past the drives?

If both of these can be had with a nice tower case, what case?