Is it better to under expose or over expose a picture?

[NLD]

I've also found that what looks blown out on the back of my lcd most of the time still has some detail there.

Yes and yes. That recovery slider in Lightroom... if you slide it all the way over... it's amazing what can come back, actually.

With the histograms, you also have to keep in mind, though, the predominant colors/tonalities of what's in your photograph. A photo of a black subject will have a histogram for correct exposure that looks different from a histogram for a correctly-exposed white subject. Correct?

 

[wenrob]

I shoot RAW and expose to the right as much as I can without blowing things. As others have said you get better results bringing it down (if you shoot RAW) then bringing it up.

If my main subject is my kids I will spot meter for their skin plus a little and give up the sky in favor of getting them right. It's all about compromise when it comes to exposure and the more experienced you become the more you'll make deliberate choices without thinking about it.