Yes, if you also plan on cooling your GPU(s) or some other part like your NB or Memory. Also if you really like overclocking it could be quite useful. I don't use it primarily do to the price and a water cooled comp being hard to transport constantly.
If you are only going to cool a CPU and it wont be OC'ed to an insane speed then a good HSF will be fine. I have a Q6600(G0) at 3.5(1.5V) and it doesn't overheat. If I was looking for 3.6+ then i would need water or something more crazy to keep it cool.