PC Hardwares life is very long(CPU can last 10-20years).
OCing and with Great Temperature Control won't cause anything bad to be happened.
Even if it minus some of the hardwares life, just be it. You will change the hardwares after a few years, so, minus it's life about 5-10years(if it's 20years life) is totally good and reasonable.

Mr. Google will help.
From what you will see when Googling, most users claim that the CPU(Processor) is very hard to die if handled properly even you OCed it.
GPU will die 1st before Processor basically. LOL.

The BEST:

Indefinitely. CPUs "die" due to the effects of electromigration. This is basically when the atoms in the circuits of a chips start to stretch apart and grow outward. Eventually, they will either break or come in contact with other circuits and short out. Depending on numerous factors, such as the manufacturing process (older and larger processes will tend to last longer), heat (less is better) and voltage (less is better), a processor could theoretically last hundreds of years, or short out in a couple minutes. Virtually all processors you will ever encounter will last far longer than the useful life of the product, so it isn't anything you'll have to worry about.

This post has been edited by DarkSilver: Apr 6 2010, 11:49 PM