The silence of the fans
I have my HTPC and the amplifiers inside a cabinet in the living room. The cabinet is well wentilated and has a specially mounted fan in the bottom to push air though it.
I have described the cabinet here and the mounting of the fan here. To put it short the fan is mounted in rubber bands to eliminate vibrations and noise.
However, I should have said "was mounted". The problem is that rubber bands need maintenance. Of course I could try to find better quality rubber bands, but I have choosen another soultion. It works fine so far, so ...