I have a 3500+ and it idles at around 36 degrees with stock AMD heatsink and fan, one 120mm intake fan, one 90mm intake fan, and one 120mm exhaust fan.
My 3200+ runs in that temperature range with stock cooling. I noticed though that after about a day of running, the CPU fan began to sound like an actual rocketship. It was even louder than my GPU fan.
There's too many factors to take into consideration to give you an average temperature, such as ambient room temperature, case location, and case airflow
i have a 3200amd that runs at 57, im having a prob with my graphics card and i think its my psu. im gonna change for a bigger one and see what happens, im also adding another fan to the front of the case to suck in air as my pc sits in a corner under my desk.