really? i mean, i don't necessarily like her, but at least its different than genta or ayumi or mitsuhiko...
genta is like the braggy annoying brat who doesn't listen
ayumi is the girl who in the face of danger only calls out to conan-kun, she is a very possessive kid who has no real point other than annoyance, also she doesn't listen to anyone elses feelings
mitsuhiko is someone who believes he is all that, and his constant sucking up to the girls is annoying,
sonoko, yes is annoying, but i think that since she is making fun of ran in good jest, not for any ill reasons, i can't really find her that bad...