it will run a lot hotter under a load.
i have a zalman9500, and with my oc, i idle at 36 and load at about 45-50(or after several hours of online chaos). and i have a ****load of fans in my case, too. better than smokin the cpu.
although the c2d may have lower load temp, but i dont think so because the idle temp is so much higher than mine.
at stock voltage, i idle at 27 and load at 38-44. but i have to really juice my cpu to get my overclock as well, and i dont think you will have to do that with your 6600.
p.s. everyone who says they will "never overclock" usually ends up doing it, im guilty too. its fun!
"nagasama no longer drinks tecate, or streaks out of the night for anything, and he has a fine wife so he has no use for your girlfriend...she is safe..."