Last year I bought an overclocked bundle from Scan, with a P8P67 motherboard and an Intel 2600K overclocked to 4.5Ghz. It came with an Arctic Freezer 13, the noise of which is starting to bug me (along with other parts of my system which I'm planning to replace). Therefore I'm looking for the absolute, bar-none quietest CPU cooler I can find - so far I've ended up looking at the Noctua NH-D14, the BeQuiet Dark Rock 2, and the Thermalright Macho HR02 (presume I'd need to replace the fan on this with a Noiseblocker or something....). I also saw a review which said that the Arctic Cooling i30 is super-quiet, but I'm not sure I believe it based on the cooler I have at the moment, which is only okay... Any advice welcome, thanks.

[moderator edit: added "cooler" to title]

I have almost the same setup as you. P8P67-Pro with a 2600K at 4.5 GHz. I'm using a Scythe Mugen 2 with two stock fans in push pull and I am very happy with it. At idle the fans are running at 200 RPM or less and are completely inaudible. At load they spin up to about 800-900 RPM which is audible but still very quiet. I use the Asus utility to keep the fans from going to max unless the CPU gets over 75, which in normal use never happens.

Thanks - I looked at the Scythe Mugen 3 but some people seem to have had issues with it (concave base being one problem mentioned) so I'm hesitant about it. Am I right in thinking that a cooler with two fans can be run at a lower speed than with one?