Just to piggyback... I've built a half-dozen systems in my life, and I'm having the same sort of boot trouble this time around. The fans come on for a second and then everthing dies - the motherboard "power" and "reset" LEDs remain lit.
I'm guessing it's a short, but I definitely have my standoffs in place. Does anyone have any suggestions? I spent hours building this thing last night, and I REALLY don't want to have to breadboard it.