Definately the spiders for me. They just have way too many legs I think
Tarantulas give me the creeps, especially. I'm always somewhat nervous of handling big boxes that have been sitting in the basement. I have 'found' many spiders that way.. and daddy longlegs.. ICK. Attractive, I don't think
I'm sure there's a multitude of venomous snake species I would be nervous to encounter.
What's funny is I have bred mice and rats and yet if I saw a wild one anywhere in the house I would probably jump and want it out right away. Especially wild rats (and I own a pet rat). Probably partly because of the association of disease.