I can build a 2.8GHZ Opteron 165 machine for the same price as your 3 drives combined, I say this is a waste of money.
Your machine does not pay for itself, in about a year, the Conroe core will blow your machine into peices. Also the 7900GTX sli is also a bad choice seeing as to how it will nto support DX10 and the 8 series is already predicted to have much high performance than the 7900 series.
just my .02, but of coures, you seem to have lots of money, so it does not look like you care.
Oh and if you don't believe me, check this out: