I was thinking about this b/c I killed a deer with a double lung for the first time. It was inside 15 yards with a rifle, and i can't help but think there might be a better way. It seems like there might be a better way(head).
To me, the best shot is a lung shot. All of my deer and most of my antelope have been lung shots and all of them have died quickly without suffering.
While a head shot might drop them quicker, I don't believe that a head shot gives you as much room for error as a chest shot does. Personally, I'd let a deer pass before I'd take a head shot.