I'm using a CNPS 9500 too and I'm not *too* impressed with it.
I'm at 44C right now in a fairly warm room though. Whats your CPU voltage set at?
Also, when applying arctic 5 thermal paste you do not want to just put a rice sized bead in the center and press it down and let it spread. Arctic 5 has revised the instructions to run a bead down the center of the processor... I have not tried the revised directions, instead I applied a fine film across the whole processor with a credit card and it lowered my temp a few more degrees.
The fan was directed such that it pushes air out the back towards the rear case fan?
The big scythe coolers for socket 775 are a joke. They use the same mounting push-pins as the stock intel heat sinks. They wont even fit on an ASUS P5B-Deluxe because they wont clear the capacitors (yes I've seen the mounting modifcation threads on other boards).
Zalman is coming out with a CNPS 9700 which is even larger than the 9500. I am not bought on the 'heatpipe' technology though. I believe a thermal advantage is gained by having the CPU heat transfer directly to the heat dissipating fin such as in the CNPS 7700.
*deep thoughts by UA_Iron*