Jerry, I had 2x 8800GTS too, and have ripped them out and replaced with a single GTX470.
Gutted tho, cos I bought the EVGA Hydrocopper Edition GTX470 (comes with mounted waterblock) for an eyewatering £475 (yes, one card, does not cook breakfast)
Have also been running an Antec Quattro 850W for the last two years with no issues, since it has to power OC'ed CPU and two waterloops, let alone the GFX card.
Stable power at all times