Just to share my experience with you. I bought Microserver kit - self-build Kuro Box, and 250Gb Harddisk. All this for mere 30,000 yen.
This microserver is little smaller than miniMac, and consumes 17watts against 60watts on miniMac. It has PowerPC 266MHz and 128Mb of Ram.
I put Debian Linux (Sarge) into it. I built this as web server (Apache + MySQL + PHP4), and run Mambo CMS. So far it runs fine. Sometimes program stops, but you can get away from it since you are asking too much from the box.
Details are here http://kurobox.com/
Worth buying if you are thinking of SOHO & Private Linux box, I think.
T.