Well, I'll be...
I'm having the same problem with my setup:
Asus AN78X-Deluxe 2.0
BIOS 1005 (non-uber)
Barton XP2800+ 333MHz
2 X 512MB Corsair XMS3200
eVGA GeForce FX 5900 Ultra 256MB
Your post causes me great relief, especially the 'runs fine in Windows' bit; I was worried that one or more of my components was bad (all of them are brand new), and that I was doomed to dance the RMA dance for months and months until I had eliminated all possible points of failure.
I'm working on a solution to this problem, but so far I don't have one. I've tried the following kernels:
with various combinations of config options; some are more stable, some less. One thing I have *not* tried, but will attempt tonight, is using the ALSA drivers for sound instead of nvaudio or the kernel i810 driver.
Whatever happens, at least you and I both know there's at least one more out here with the same problem. If I get my box up and running in a stable manner, I will definitely post a step-by-step recipe here.
best of luck!