The Fit-PC2 by CompuLabs is a great home server.  Why?  The design of being small, compact makes it ideal to have it anywhere in your home office.  The device only needs 6 to 10 watts of power!!!  When the device is in hypernation mode it only needs 1 watt of power.  That rocks!  Finally, it runs Ubuntu Linux.  So this means you get the latest and greatest in free, powerful software.  Yeah, Windows pays my bills.  But for a server you want running 24/7 that is at your finger tips as a file server, you cannot beat this little beast.  http://www.fit-pc.com/web/  to view more information.