My Machine has been overclocked for 2 years My CPU is a Intel I7 920 D0 2.66MHz I have a mild over clock of 3.0 on it. I have in the past run it at 3.9 for well over 8 months with no problems this CPU chip is built for overclocking
I have Mushkin redlines DDR 3 1600 MHZ triple channel Memory which is current over clocked to 1703 MHZ and never had a problem this memory is great for over clocking.
My GTX 260 Video card stock 576MHz is running at 656 MHZ currently I ran it for a year at 640 MHz with no problems.
I would say you experience was your old equipment or was just a unique situation. Many users overclock and run their overclocks 24/7 whith out having any problems.