very interesting thread. i was about to ask a very similar question.
i am about to get myself some sound dampening mats for my case (chieftec midi tower, in case anyone wonders).
my system currently has relatively nice specs and no additional case fan, but i reckon that with the extra mats i will definitely need one.
is the general view then that for this kind of exercise a yate loon 120mm fan would be good (or maybe 80mm, i have to measure my case first)? or better a nocturna one? price really isn't the issue here. it should just keep the entire system stable but be as quiet as humanly possible...
also, i am relatively new to the idea of modding my pc and read further up in the thread something about a fan controller to regulate the rpms. what exactly is this?