You may remember I've been mumbling and muttering about where and how to find low powered motherboards and/or complete systems for use as servers (disk NAS plus other services).
I've just bought one of these:-
http://www.morgancomputers.co.uk/product_detail/15265/Fujitsu-EsPrimo-P910-Q...
I got an extra 10% off (easy, just look for Morgan promotions) so it cost me about £276.
It's excellent, silent most of the time as the fans don't run unless you work it hard and, even better, the idle power consumption is only 24 watts. There's space for several more drives in the case. It would make an excellent little server machine. I'm actually going to use it as my desktop machine, it's quite fast enough for all the things I do.