nitrousoxide10

Stunning build! The colors look fantastic together.

I agree with the previous posts. For that price, go APU. If you are planning to add a dedicated GPU later, then don't bother spending the extra money for 1866 RAM. 

Yes thats a pretty nice psu and 80plus gold you can take that

It could be the power supply. Especially if, when it doesn't start, you hit the reset button, and then it starts. It wouldn't be a major fault in the PSU, but just a problem with the timing of the "power good" and/or the reset signal.

Could possibly be the Ram, try running some test on them one by one with Memtest86 to see if any errors occur.

get bluescreen view and look at the dumplog 
http://www.nirsoft.net/utils/blue_screen_view.html
the download is about 3/4 the way down the page.
 
it should highlight the error if you want zip the log and link it here.
from there you can start looking for a solution.
 
btw 80'c isnt hot its very warm for that card but its still 20+'c from throttling or shutting down.
you will want to clean out any dust with compressed air and increase your fanspeed about 10% across the board if you can. with something like msi afterburners fan contoler.

First thing I would suggest is swap the power supply.

Ya some specs would help a lot. If you have multiple sticks of RAM, remove all of them and repopulate one dimm with a known good module. 
 
Have you tried unplugging everything except the components you absolutely need to post? 

Yes it is very possible for a power supply to be functional enough to power up the computer, but not functional enough to allow the components hooked up to it to live for a long time.
 
You should post the model of your power supply. Generic power supplies tend to do this more often than high quality brand name ones.