It is a good idea, sometimes the manufacturer's don't do such a good job applying the thermal interface material (TIM).

First you'll need this to remove the old TIM. You should use a lint free cloth to clean up the residue. Be sure the surface is completely clean and dry before you apply the new TIM.

Next, you'll want this. New MX-3, great stuff. Works on cpu, gpu, chipsets, mosfets, etc etc. Be careful when applying it to small chips, you don't want to bridge metal. You should search out a tutorial to discover how to apply it for best effect.

Not all chips need cooling, generally you only need TIM on places already covered by a heatsink, don't worry about bare chips.

If you want your temps to stay down, consider watercooling, or at least an aftermarket air cooler for your CPU..

If you find you need additional help, there's tons of info here on the forums, and dozens of people willing to help you out.

Hope this helps.

If you are not having temp problems don't fix what isn't broken. However, if you plan some extreme overclocking its never a bad idea.

Here's a couple pics of my old EVGA 680i SLI when I was swapping on some aftermarket sinks. My NB was getting pretty heated, so I figured a Nice tower sink would be great. And it was great, with a 60mm fan at 40% fan speed, moved just enough air to keep it cool. I also used MX-2 Thermal on everything.

Remember, do not do anything like this without doing research on it first. As much information as you can find about your particular motherboard is still not enough for you to be prepared. I have swapped thermal on 3 different motherboards and all 3 were a different experience. Also, if you are buying an aftermarket sink, be sure that it fits your particular board, not all boards of the same type (680i, 750i, x58, ect...) have the same holes.