My first instinct is the PSU.
Does the PSU have active PFC?
I don't think that my psu has active pfc. But just to make sure, here is a picture of the back of my power supply.http://i.imgur.com/PW3EA.jpg
I do not see any burn marks on the motherboard or components, so hopefully it was just the power supply that died. Do you think that there might be a reasonable chance that the psu took another component with it, such as the motherboard?