I would have to agree about the Atheris hispida just because of their looks, what a mesmerizing snake that is!
But there are so many intriguing snakes! Like the Golden sea snake, that can see predators coming.. With its tail! Or the Erpeton tentaculatum, (tentacle snake) with those awesome tentacles that detect prey, and it just lashes out lightning fast to catch it. And who can forget the ' flying snake' that can glide 100 meters by spreading out its ribs?
So many awesome snakes...