Originally posted by: paydirt
I'd go buy a bunch of Thermaltake Smart2 fans, 80mm or 120mm, they come with adjustable speed controllers. About $11 a pop on the 120mm's at newegg.com
Bad idea -- these fans are anything but silent, even at their slowest speed. Their motors and bearings are very noisy. I recommend Evercool's "Ever Green" case fans (the green ones) -- they're very quiet even at 12V, and could be silent if run from the PSU's 5V rail. I use the 92mm and 120mm fans in my own rig, as well as the USB-programmable MCubed TBalancer BigNG microprocessor fan controller.
The 5V mod is one that I recommend you look into. The 7V mod doesn't always play nicely with every type of power supply, so the 5V mod is much safer, though not every fan will start reliably at 5 volts. The Panaflo L1A-speed fans is a good candidate for operation at 5V, and it was the original favorite over at Silent PC Review.
Don't expect a whole lot of airflow, however. You'll sacrifice some of your thermal performance for decreased noise, especially with a case that has 80mm case fans. What case do you have? Would you consider a new case, like an Antec P180 or SOLO?