There's an interesting study which was appeared in National Geographic over 10 years ago:
http://news.nationalgeographic.com/news/2001/10/1004_snakefears.html tl;dr: Snakes haven't really evolved in a significant way in quite a long time. Over eons of evolution of mammals, snakes were a persistent danger to them, thus mammals, in general, are predisposed to fear of snakes. We can spot their slithering motion more than other small animals based on this evolutionary drive, and the phobias against them are deeply rooted in our genetic makeup.
It's not surprising that people tend to be have a rather polar bias with snakes; many give in to that primal fear and never overcome it while others are likely attracted to them for the very reason that they trigger such reactions deep in their minds, as well as the very fact that they are so very primitive yet seem so deadly.
I know the people who read this are not really a "typical" sample of the human population, but I'm curious as to people's reactions to snakes, so I'm going to try another poll. This one's even a bit shorter. Thanks again... It's interesting to see what this community thinks about this sort of thing.
EDIT: Replace the "snake" in the first answer to the last question with whatever animal applies.
Poll Attitudes towards those of the serpentine nature