I use/sold a lot of linux home servers

The hardware is a shuttle k45 barebone with 1 Gb ram and a low power intel cpu and 2 identical disks ( from 500Gb to 2Tb each).

I run hardy 8.04 on them. I set up software raid 1 (/ and swap part).
-ssh shell and webmin for administration
-samba for file sharing
-mediatomb/ampache for music streaming to pc/console
-imap mail server with postfix/dovecot to make mail accesible evrywhere
-with cronjobs I handle automatic backups & auto shutdown from 23:55 to 7:30 (powersave)
-I'm in the middle of trying to get funambol running for phone/calendar /mai syncing

There's a steep learning curve if you're only used to windows systems, but these systems out perform windows by price (licensing costs), flexibility (wat can't be achieved?) and stability (viruses? crashes?)

I access the severs features from the outside via my dd-wrt enabled router that runs dns and a vpn server.

If you want to know more I'd be glad to go more into specifics.
This servers uses at minimum 35 watt (according to shuttle). But a average server with 2x 1Tb and celeron processor uses 55 watts in my experience.