Well chokes are a different matter and to be honest the topic of this post does imply punching. However to take up your comment about kicks, most people don't kick nearly hard enough to the head to knock someone out. Compared to punches ive seen VERY few people cleaned out with a head kick, especialy a side snap or thrust kick as you suggest. Ok it might break teeth or a nose but unless the opponent is walking right onto it, im very sceptical about this being a prime knockout technique. Further more as this is a self defence forum, what would anyone be doing kicking to the head in a self defence scenario?