Most articles dealt with making a computer as quiet as possible such as How to Silence a Computer and Building a Silent Media PC. Others deal with award-winning design concepts.
But for the Piece de Resistance, The Ionic System Cooler went all out to make a true, working 0dBA system. Here is an update to the above article, The Ion Cooler 2.0. Now that's some cool stuff.
To continue researching on your own, how about a site dedicated to Building a Silent PC? Or, for quiet product info, try the Silent PC Review.