Building a box for a Net drive

So I've been thinking about building a box for a net drive at home for
photography and graphic art storage and such. I have an ASUS A7V600X-E board
here and a 2400 Athlon and three 256M sticks of various PC2100 and 2700 RAM.
I was going to put Windows 2000 Pro on an IDE 8.4G or 10G drive and put two
640G WD Blue or two 750G WD Green drives on the two SATA ports.

Originally I was going to RAID them (even though I've never done that) and
map them as a net drive on two of the XP Home machines here (never done that
either). I read a review on the Green drives that suggests they don't like
RAID and the constant running shortens the life span and makes extra heat
(and noise to cool them). So I was thinking that I have a copy of Acronis
True Image 9.0 here that's not doing anything and wondered if I could just
map one of the drives and somehow tell Acronis to keep them mirrored
incrementally every day thereby keeping a safe copy and yet working them
less and getting another 110Gigs for the same money.

Is that a better option?

Anything else I need to think about?