I was spanked. I think the key to spanking being of benefit is the way it is used. My parents never did it in public, and never for frivolous reasons. When we got it, we had been truly disrespectful/in need of a spanking! And we knew it was coming. There was always that time period waiting for it, the tension, the fear in waiting, which was always much worse than the spanking.
Usually, just hearing my dad mention it would get me in line. It obviously was not pleasant. I see a lot of parents now who will go spank their kid for anything, at any time...after awhile, the kid is like "big deal" and it no longer works.
So yes, I was spanked, it was not the cornerstone of my parent's discipline, but it was used at times, and I do not think they were wrong.