Well I built a machine!
I went for the Antec case in the end because it was in stock at Novatech at the same price as eBuyer.
It's got an Asus P5Q SE2 inside, along with 4GB DDR2 and a Core2Quad at 2.66GHz.
I am loving having one RDP session on each work space in OS X - with OS X itself and all the VMs totally responsive. Before, when I was using vmWare the whole machine would grind to a halt with a VM or two open.
XenServer installed first time, so that made all the searching of HCLs worth it. Thanks to Spreadie who I bought some parts off and generously threw in a NIC which works nicely with Xen.
The motherboard is ICH10 based so it supports 16GB of ram. So I'll be sticking some more in it when I can afford to.
Thanks for the help everybody.
