ms - thanks for the very nice list!
The total PS wattage doesn't matter, rather, the +12V supply is what matters. It looks like this PS gives 27A max of +12V, which may or may not be enough under high-current-draw conditions (such as overclocking). So, it might be the PS.
Also, have you tried monitoring CPU, GPU, and general system temps? More likely than the PS is that perhaps the GPU is overheating? If this is the correct video card you have:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127300
then it could certainly be overheating under OC conditions if you don't have enough airflow in your case to (a) exhaust enough hot air from your case and (b) blow enough air over the heatsink of the video card. Especially with all that stuff (hard drives, extra tuners, etc) in your case, unless you have at least 2-3 120mm exhaust fans, I bet it gets pretty toasty inside that case.
On a related note, since you are using a CPU cooler that does not perform the secondary cooling of nearby components (e.g. north bridge and PWM area) that the stock Intel cooler does, you could be seeing problems due to northbridge and/or PWM area overheating.
Finally, is your MB one of the Gigabyte boards with their new "energy saving" features? If so, I've seen a number of posts that the technology doesn't work right yet, and instead causes crashes.