AltaTac via eBay offers the refurbished HP Z400 Workstation Intel Xeon 3.2GHz Desktop PC (no monitor) for $439.99 with free shipping. That's the lowest total price we've seen for a Xeon quad-core HP with 12GB RAM, and $86 under a similar refurb elsewhere. It features an Intel Xeon W3565 3.2GHz quad-core processor, 12GB RAM, two 1TB hard drives, DVD burner, NVIDIA Quadro FX 1800 768MB video card, and Windows 7 Professional 64-bit.

A 90-day warranty applies, although it's unclear who supports it.