Being a fan of snakes, I do feel obligated to say that snakes aren't as bad as some people think. It's like the hysteria that kept people from the beaches after Jaws came out. The venomous ones are certainly no laughing matter, but aren't quite the spawn of satan they are made out to be either.
Thats the beauty of North America. The hot snakes are easily identified by that triangular head shape. It's the venom glands, makes the back of there cheeks stick out. Also the slit pupil vs. a round pupil, but who gets that close to a snake that hasn't already identified it right?
Remember this only applies to North America. Anywhere else in the world, all bets are off. Oh yeah, and Florida too... might be easier to identify what doesn't live there, eh?