ASRock E350M1 Mini-ITX Dual Core Motherboard With Antec ISK-100 Micro-ATX Case for sale.
At a glance:
1.6GHZ dual core E-350 processor with integrate graphics
Antec ISK-100 micro atx case with 90 watt power supply.
2GB DDR3 1333 RAM (board supports 1066, but 1333 is what I had lying around & 4GB works better)
160GB Hard Drive that could cheaply be swapped for a 1TB offering if converting the machine for home theatre or home server use.
This item is listed on ebay and is only delivered within the UK. Current bid stands at £21 with £10.30 for 1st class delivery.