Core Temp 1.15.1
Core Temp is a compact, no fuss, small footprint program to monitor CPU temperature.
The uniqueness of it is that it shows the temperature of each individual core in a each processor in your system! You can see in real time how the CPU temperature varies when you load your CPU. It's also completely motherboard independent.
ntel and AMD recently published detailed, public information about the "DTS" (Digital Thermal Sensor), which provides much higher accuracy and more relevant temperature reading than the standard thermal diode sensors do. (How it works).
This feature is supported on all Intel Core and Core 2 based processors as well as the whole AMD's Athlon64 line of CPUs.