I mostly have taken neck shots because when I was a kid my father and uncle both commented, "If you shoot him in the white spot, he doesn't go anywhere." I've seen my father hit the white spot, offhand, at around 250 yards. I watched my uncle break a buck's neck at right at 75 yards as the buck jumped over a fence.
However, out beyond 100 yards, I go for the heart/lung shot--which with my '06 has been pretty much a "go nowhere" deal.
I guess I've tagged somewhere around 50 bucks through the years of hunting in Texas, mostly back during the two-buck limit days. And some years of mule deer with a one-buck limit. I've never had to trail a deer.
You're from BATFE? Come right in! I use all your fine products!