I don't know if you would consider D from Vampire hunter D a goth but he does fit the bill,he wears all black he's a loner,a lil' moody and a vampire.So if he counts then it's him and if not then probably Damian southpark.
Damien's not goth. He's The Omen.
Emily Osment in 'The Evil Thing'. Anyone notice that the kind of central goth kid on south park is slightly modeled after the guy from The Jesus And Mary Chain? Ah, I don't know who else right now, I can't remember.