After my first attempt at a quiet(er) Home Theatre Performance PC, I've gone back and made a few changes including:
1) Removed TT Big Typhoon for a Scythe Ninja HSF w/ YL fan. This helps with the airflow from front to rear.
2) Removed the TT iCage HDD mounts for a home made elastic chord HDD suspension setup. This incorporates a Scythe Kama Bay front HDD 120mm fan (YL again).
3) Replaced old PS w/ a newer Silverstone Element PSU based on the Enhance 80+ unit and mounted it externally as well, w/ a Panaflo 120mm fan (this will be replaced with a YL also). I found out my PSU was one of hottest components in the system directly contributing to more stale ambient air.
Note: bottom intake fan is actually not operational and will be removed, as will the AC silencer on the 7900gt for a completely passive hsf. I'm also working on a CPU ducting solution soon. All fans are directly controlled via Speedfan for further noise reduction.