Just a thought for anyone working through this thread.
The quad isn't needed for almost any trading app and the latest core2duo's give you better outright cpu speed with much lower power consumption for lower bucks than the q6600s. Try an 8400.
Also the 8000 series graphics cards are not really needed for anything except the latest games at highest resolution so you can save a bit on dollars and power consumption with the 7300GS or 7900GS instead.
Finally the Raptor and (newest) Velociraptor hard drives are extremely fast which again is almost irrelevant to trading. In return for speed they are noisy, power hungry and have lower bang for the buck (the sweet spot for hds seems to be about 500GBytes from Seagate or Western Digital (possibly less reliable than SG).
Green is good; so is quiet
