Those temperatures are 100% normal. I also own that same processor. Remember that Prime95 is a worst case scenario for the processor. While it might push the temps to the mid 60s there are very few programs that will ever stress the CPU that much, so typical load temperatures will be closer to the low or mid 50s.
Oh, by the way, that 66.7 celcius secification from Intel is actually the T-Case temperature, not the core temperatues. In order for the T-Case to get to 66.7, the core temps would need to be 85+ celcius