And spiders. Not those little ones you see around your house, but the big, hairy bastards. *ugh* Snakes, alligators, lizards, big bugs, rats; I can handle all of those, but spiders creep me the hell out.
My wife says that once they're big enough that you can see their knees and ankles "articulating", the scream can not be suppressed! :)
I can't tell you now many spiders I've dispatched over the years at bedtime. My daughter always makes a quick spider-survey of the ceiling and walls before she'll go to bed.