I used a E5200 and a scythe mini ninja. One of my temp sensors are stuck on my CPU (at 55c), but the other core idles at 36-37c, and load temp after 30mins of everest stability test it gets to 44-45c. I think the mobo temp is always around the 34c mark.
I also have the Asus Qfan controller one of the noctua 1200rpm fans which runs around 800rpm, and I have a resistor cable on the other fan which I think makes it 500rpm.
Re-reading, fobose's post it would seem that the scythe mini ninja does the job pretty well - but i get the impression his case fans are running all the time, but at lower rpm.
In fact his temps are ideal, considering it's all passive.
But if you can't hear your zalman, when the unit is in situ, you should be fine with your setup?