depends on where you live for the cost of your power.

OCing = free performance. If you've got the time and "know how", do it. It can even be fun.

The Core 2 is a lot more efficient (better designed) processor than your Celeron..bacon aint all just about speed.

Ya #17 you're an rodeo cowboy and you suck at the internet... go do some research.

#20 & #23 good job, you understood half of my post..

the extra volt of power to OC these arent going to cause a brown out in your area... youll have a bigger electricity bill if you have a 1000W + power supply hooked up to your rig compared to a 750 or 800. Some power supplies are more efficient at what power is used. Plus the new CPUs arent as power hungry as they used to be.

Quads arent necessarily faster than a Core Duo, just means that you can multitask multiple things at once if your a dork who wants to watch video, play a game, rip a DVD and have your webcam streaming you stroking your quarter incher over the web showing how much of a man you really arent.
Im not sold on the quads just yet... they arent being utilized to their full potential yet... plus they are harder to OC.

#20 and #23,

Please re-read comment #17.

#11, Over-clocking does NOT decrease the lifespan of a CPU, Heat does. If cooled properly it will run as long or longer than if ran @ specs. Is that enuf schoolin for ya today?