Re: Post your 3DMark01SE, 3DMark03, and 3DMark05 Scores.
It does shorten the life to a degree, but not anytime soon. It's like a car. People like me who put superchargers or turbos in their cars reduce the life of the motor, tranny, fuel pump, etc because they are pushing their cars more than what's intended for stock specs. Parts wear out quicker because of the increased force applied to it. But it's not going to break down like next year or that soon. Some overclocked parts lasts for a long time when you do it safely. I wouldn't worry about it if you want to OC your card. I OCed mine and it was fun.
In PC's case, it's the heat issue that shortens the life when you OC it instead of the mechanical wear and tear. If you have adequate cooling and it doesn't peak too high at it's critical stages, your GPU will have a decent life cycle.
*Fact: Microsoft Window's Blue Screen of Death vs Computerforums.org's White Screen of Death. Which is worse?