mensch
The HP Microserver is great - been recommended here by several people (including me, of course)
HP N40L or HP N54L - even the N36L.
Available as a single disk, 2 Gb RAM box for about $300 in Australia.
I have 2 at home (with 2 x 2Tb drives, 4Gb RAM ) that have performed faultlessly now for over 12 months. I have also introduced them into 2 places I support voluntarily (remote access via SSH), where they are on 24x7 without a hitch.
Chers
Ian