Since my last post, I've replaced: Radiator fans (2x 120mm) and front intake fans (2x 140mm) with Noctua fans (believe the hype, they're amazing). I left the AF140 Quiet Edition on the exhaust slot because it's indeed quiet, looks good and gets the job done.
I also replaced my CS750M power supply with the more dependable HX850i. This PSU features fan-less operation up to near max load.
My PC is now of the "quiet" category!
Future Updates: Not really sure where to take it from here. I considered upgrading to an i7 4790K but that would do me no good since this is a gaming build and the performance gain would be negligible from my i5 4690K (OC'ed 4.4Ghz @ 1.150V). I game at 1080p, 60hz so replacing my GTX770 is unnecessary at this time.
I guess the next thing may be upgrading my gaming monitor to a 2k or 4k but that would be an expensive investment that would need to be followed by a GTX 980 or 980ti, so easily $1K to make that move.
I do plan to upgrade my storage to 2x 2TB HDD, I wanted 2x 3TB but I hear nothing but horror stories about 3TB drives.
That's all folks!
UPDATE: I ended up upgrading to an i7 4790K which is in my current build.
UPDATE: I've swapped out the 2TB WD Green in favor of a 3TB Seagate.
UPDATE: Swapped the Asus 770 for a Ghz Edition 780ti