Ariados is my favourite of the evolved bugs, so I'll go with Spinarak on this poll. Most of the first-bugs, in and of themselves, I find annoying, but Spinarak was always kinda cool in that it was the first to come out mainly at night, and it's sort of cute without being super-annoying. (I'm looking at you, Weedle!) I really dislike the newer bugs, so it was always between this and Caterpie; as I'm not the biggest Butterfree fan, Spinarak gets my vote.