I am going to stick in another suggestion.
A Llano A4 3400 and an A55 based motherboard:
http://www.ebuyer.com/282388-amd-lla...-ad3400ojgxbox
http://www.ebuyer.com/279251-gigabyt...rd-ga-a55m-s2v
The motherboard comes with 6 SATA 2.0 ports and can run dual monitors AFAIK.
For another £5 more you can have an A75 based motherboard with 6 SATA3.0 ports and 4 USB3.0 ports instead:
http://www.ebuyer.com/274047-asrock-...board-a75m-hvs
The Llano CPUs have relatively low power consumption under idle too.