I usually always go for the high percentage shot, which is the shoulder/lung area. This a big target and usually drops the animal with in 100yds and often less then 50yds, even sooner most of the time when the shoulder is hit.
However, I have taken head and neck shots on occasion, usually when I felt like I needed to drop the animal right there on the spot. I did this last year while hunting around some deep ditches, that would have made it very hard to drag a deer out of, and would have more then likely been the final resting place of any lungshot deer. The range was close, so I took neck shots at the base of the head. This always dropped the deer right in it's tracks, and I didn't have to go into the deep ditches to retrieve a deer.
I do not favor neck shots or head shots as a general rule, because for one thing, the idea that a neck shot or a head shot always drops a deer on the spot or you missed is a myth. I have seem deer with blown off jaws still walking around, to die of hunger or something else, and I once shot a deer with a blackkpowder rifle in the neck by accident, I hit the deer hard, 4 inches into it's neck, with a 54 cal roundball and it bled like a stuck hog, and ran off. My hunting buddy killed it, later in the morning, while it was just walking along, a full 200yds away. I would have never gotten that deer.
So don't take neck and head shots, thinking that it is always a miss or an instant kill, because it just isn't so, not always. I only take one when I know for dead certian that I will hit exactly where I am aiming.