<a href=showthread.php?s=&postid=8874067#post8874067 target=_blank>Originally posted</a> by "Umm, fish?"
The big deal with the histogram is to make sure that both ends go down to zero before they run off the graph. If either end is greater than zero, that means that you'll lose detail in parts of your photo (one side means that you'll lose detail in the whites, one side means you'll lose detail in the blacks).
Good luck!