I'm looking for a pretty good case fan to cool my ATI Radeon HD 7950. (I know there are aftermarket cooling solutions for the card, but I don't have the time or money to buy and install one.)
My GPU usually heats up to 68C+ under heavy load - it is able to maintain around 64-66C with a window fan blowing 75F air into the case. After fiddling around with things, I came to the conclusion that my case probably needs better air flow to keep things cool.
My case is the Corsair Carbide Series 300R case (non-windowed). I have two side mounts for intake, one (or two?) fan(s) in the front for intake, two mounts for exhaust on the top, and one fan in the back for exhaust. I'm mainly interested in fitting a 120mm-140mm case fan to the side mounts, and possibly replacing the fan in the front as well. (I'm not sure if I would want/need to replace or add exhaust fans.)
As for fan noise, I generally prefer quiet fans, but I'm willing to settle with a fan with moderate noise if it provides more air flow to my case. (Please offer both options in your suggestions!)
I'm runing a full case of Cougar fans and i've been very happy with them, they're dead silent at low speeds, and even at higher speed they're very quiet...They move lots of air and are a bit more affordable that most quiet high-performance fans:
I have that same case, and I haven't had luck with finding a fan that doesn't produce a high-pitched whine from sucking air through that grate. If you haven't filled up both 140mm slots in the lower front yet, I would do that first. I, too, am a big fan of Cougar and I think they would have an excellent application there.