PC Probe 2 is okay so long as you don't want to adjust anything, it's almost purely a monitoring utility since about the only thing you can sort of adjust is the CPU fan. Sort of depending on whether or not Q-Fan is enabled. If it's enabled, you can use PC Probe 2 to set a predetermined CPU temp that if reached will tell Q-Fan to increase the CPU's fan speed. The theory being that Q-Fan will intelligently adjust CPU fan speed (higher or lower) depending on the CPU temp. Whether or not you use it will depend on if you believe any number of talks about it. Some people say yay, some say nay. Your choice.
But if all you want to do is pure monitoring (CPU temp, MB temp, CPU fan speed, Chipset fan speed, Chasis fan speed, different voltages), in Windows, in real time, and all at once, then as far as costs go PC Probe 2 is pretty decent since it's free.