Although I recall taking a few extra MHz on two different 486 processors back in the day, for me the golden age of overclocking came with the venerable Celeron 300A that received a healthy boost to 450MHz without much effort. If not for saving a few bucks, squeezing every bit of untapped performance in a processor has always brought a certain sense of enjoyment. In spite of that, my last two systems have run at factory settings as I haven't bothered to look past stock cooling options and simply gone with 24/7 rock solid stability. On the GPU front, I've rarely resorted to overclocking because I tend to upgrade often, but in certain special scenarios (think Crysis) every bit of extra headroom helps.
But how about yourself? Tell us what's your take on overclocking these days, whether you overclock your PC (or not) and why. Discuss.