I would never consider a head shot, no matter what size the deer was.

I have had several shots at deer (4 big bucks and a doe) where they were 4-6 yards, facing me. I would aim right between the shoulder blades for a spine shot or a one lung shot if I was a bit off to one side. On my last encounter with this shot it was a 150+ 10 point. He was 4 yards out and I had to grunt him to a stop. He looked up at me as I was squeezing off the shot. When the shot went off, he swung his head as he was bolting and his antlers grabbed the arrow and scrubbed all the speed off of it and only penetrated about 3 inches. He ran off with my arrow which looked like a harpoon in his back and was never found. Neither was the arrow.

I WILL NEVER TAKE THAT SHOT AGAIN.

4/5 times it was sucessful but that one time that it failed made me realize that the animal deserves more respect than that. I was extremely disgusted with myself. Never again. I learned my lesson the hard way.