You gotta go with the Zalman 7000. It's the top-dog P4 HSF and runs quiet even at full speed plus it comes with a Zalman Fanmate (reostat) so you can adjust the fan speed to suit your taste of noise vs. temp.
Another great choice (and the one I use on my 3.0C/P4P800-D) is the Thermalright SLK900U, or the slightly redesigned (for clearance on some problematical mobos) SLK947. These heatsinks let you mount your choice of any 80mm or 92mm fan on them. I'm using the insanely quiet 92mm Panaflo L1A on mine and it's running at 8V. Idle temps run in the low to mid 30°C range and Prime95 load temps run in the mid 50°C range at 78-80°F ambient temp.