Well, it depends on what price U R getting it
I m suing a Zalman CNPS AlCu-7000 HSF with a P4 3.06 GHz Northwood, it is really cool & quite HSF
The max RPM of my fan is 2500 RPM, but during cold, these days, it runs at arround 1800 RPM, I monitor it via my motherboard hardware monitoring chip, which also controls the fan RPM depending on Heat deception. Overall it is inaudible in cold, during these months, even in summer it is quite, the max temprature I got ever was 51C which was when I was encoding a mpeg2 file