Well this is overclockers, and because overclocking does generate more heat. More cooling is required. More voltage is required, hense more heat, so we need better cooling. Also systems reach high overclocking speeds when cooled better, so more cooling. System run with less problems, so we keep them cooler.
Im my liquid cooled T-Bird I have about 125.00 and my air cooled Duron about 55.00 and about 2 hours of case mods. Both run less than 44 degrees all the time.
The better your cooling, the more you can overclock and the longer your components last. I probably have well over $100 US into my cooling mods, and I'm strictly an air cooler guy. GlobalWin FOP with 80mm Sunon High Output fan, 92mm Panaflow front lower intake case fan, twin intake 50mm fans in the upper front of the case, a slot fan, rear 60mm exhaust fan, 40mm northbridge fan on the greenie, Blue Orb on my video card, heatsinks on my video RAM, southbridge chip, and ICS clock generator, rounded data cables, and power supply fan (which is not figured into the costs). Oh yeah, forgot to include the Arctic Silver thermal paste and Arctic Silver epoxy.
I have probally spent about 200-300 bucks on cooling, but that is for 4 comps
circuts work better at lower temps, the optimum temp fot a mother board to run at is about 5 degrees celcius, anything lower and particles start to slow down ect. but the cooler you can get your case, the better/longer your components will last