I wouldn't trust a dual 7800GTX SLI setup, and I'd feel better with more wattage if I had an Intel - especially top end, but a decent A64 gaming rig with a reasonable video card (though I'd really want more wattage with a 7xxx series) and one or 2 drivesm, maybe. Its not so much the average draw (which is only around 200 even on a pretty loaded system) but startup draw.
PCP&C makes top quality stuff. If money was no object I'd want them in everything. But I just don't know if this one is able to handle the peaks. I'd feel better with 350+.
Mike.