A X8DAi motherboard with two Engineering Sample Xeon x5550 cooled by two Thermalright HR-01X. 12GBs of 1333mhz ram, 2 WD 150GB Velociraptors in Raid 0, a Nvidia Quadro FX4600, all powered by a Zalman 600 watt psu.
i'm kind of surprised the 600 watt psu does the job, when i was building people were constantly telling me to get 1000+ watt power supplies.