If you have a powerful desktop, it probably sounds like a jet engine. You could opt for watercooling, but if you stick with fans you're out of luck. They're just loud. Until you bolt on some active noise-cancelling.
Produced by enthusiast CPU-cooler pros, Noctua, with some help from RotoSub, the cooling unit is only a prototype, but popped up at this year's Computex in working order. Thanks to a built-in microphone that picks up on the fan's hum, and a set of speakers that put out a phase-shifted sound to cancel it out, the little miracle worker can take fans from BZZZZZ to damn near silent at the press of a button.
It's a clever solution to a pretty annoying problem, but you can bet that when it hits the market it's going to come at a hefty price. But exactly how much it'll be, and when you can get one is still TBD. Rf silence is really golden though, maybe it'll be worth it.