I am using the Zalman CNPS-9700 HSF. Works pretty well but I had to slightly modify things to get it to fit.

There is a spring clip tab on the mounting bracket that is intended for use on an AM2 mount. The tab stuck out just far enough to bump into the mosfet cooler fins. I trimmed down the tab since I'm not using an AM2 proc. It's plastic and easy to shave down and once the tab is shortened the bracket fits.

The second thing I had to modify was the cooling fan on the NB. With the fan squared over the NB HS the NB fan interferes with the fins on the Zalman HSF. To work around that I am using one screw on the NB fan on the upper right corner. By rotating the fan down about 30 degrees the fan still blows across the NB but does not interfere with the fins on the Zalman cooler.