I have been using these big honking Noctua coolers for my last two build. They are truly completely silent when idle. You have to put your head directly next to

I have been using these big honking Noctua coolers for my last two build. They are truly completely silent when idle. You have to put your head directly next to the case to hear them at all when you're just browsing or doing light tasks. And they only give a reasonable amount of clean fan noise when running max. No squeaking or annoying peaking frequencies. Coupled with high quality power supplies that are also virtually silent, this makes for dream PCs.