Fantastic, thanks. Based on the cost, and them using almost the same amount of power as my current file server, it seems like a great buy. Just got to decide which oneThe Dual Core versions I have use roughly 90Watts idle and 120ish under load. A quick google shows the Quad Core version to idle around 88-99Watts and load upto 140 although the author mentioned that he wasn't sure of the load levels when he took the readings.
http://www.techhead.co.uk/installing-vmware-esx-and-esxi-35-on-an-hp-proliant-ml115-g5-quad-core