on the quiet fan note: i cracked open my power supply bacause it was the only thing making any real noise in my box, and when i did open it, i found an Adda fan in there. when i saw this, i thought, "hey, but Adda fans are quiet, the people on Anadtech forums are always goin on bout them, so why is mine so loud?". so, i unscrewed it from the psu, sat it next to it on the table, booted it up, and.....silence......nowt. i put it back, lots of noise.
the moral of the story here is, u can have a really quiet fan, but if the power supply hasn't got good ways for the air to move round, then it will just create turbulence, and therefore, noise.
as for the unplugging of it - don't, UNLESS u have very good airflow in the case anyway