I have recently started putting together a core i5 rig:

Intel Core i5 2.66 GHz cpu

Asus P7P55D Pro LGA Mobo

G.Skill 4GB DDR3 1600 memory

Corsair 650 Watt psu

WD Caviar Black 750GB hdd

I'm still up in the air on which gpu I'll be getting, (torn between the HD 4870 1GB, and GTX 275 896GB), but that's another issue. Anyways, I've read on http://www.overclockersclub.com/reviews/intel_corei5750_corei7870/4.htm
that the i5 can be safely overclocked to over 4Ghz. I'm not sure I need to go that high and would like to stay around 3.6-3.8Ghz. I also saw this video
on overclocking the i5. My question is, does anyone think this video and the overclockersclub site have any validity? I haven't overclocked a PC in about 4 years (which is how old my last desktop, prior to the i5 rig, is).

You could read the article Overclocking Intel's Core i5-750 & i7-870. It might give you a better idea.

Overclockers Club is a trusted website.

EDIT: Here, I found another one. It discusses your motherboard as well I guess. Overclocking Intel's Core i5 750.

Thanks for the links. This further confirms what all the other sites are saying. Also worth note, is now I will be able to surpass the 3.7Ghz range I was aiming for and go all the way to 4Ghz and still be stable! (Just have to spend a little extra to get a better CPU fan and heatsink)

grab the gtx 275 its quite a bit faster than the 4870 and ill last you longer