After re-watching season 3 lately, I have to definitely, without-a-doubt say JOHNNY. I didnt mind him up until 'The Game Plan' but then after that, he had to go. He made Marissa and M/R look bad, dragged down the show and was just stupid. He also ruined Chrissmukkah and I didnt find Kaitlin/Johnny interesting at all (Im not 12). They shouldve just had him leave on his surf tour and they couldve had M/R break up over Trey or something good instead of another third party, if need be. Oliver at least was interesting and a good actor but Johnny just..did nothing for s3 and it dragged down the whole season as a result. Theres a reason why the season picked up after he died. If they wanted to interject some more drama with the 'getting run over thing' at the end of TGP, why not have it be Summer? It would cause a cliffhanger since people like her (did people really care to stay tuned to see if Johnny made it or not?) like Kirsten and her car accident and it would be nice to see Seth take care of her while she's laying up in bed since it always seemed like shes always the victor in the relationship while hes always lying and whatever. Anyway, Id say him.
Che still bugs but I dont watch s4 much so I always end up forgetting about him. Actually I didnt mind HIM so much as that stupid SL with Seth finding his inner animal or whatever the heck it was. And at least he helped Summer get kicked out so she could go back to Newport.
Jess Sathers still bugs me but at least she brought some much needed drama to the end of s2. So I dont hate her anymore.
Charlotte I think could have been good if they utilized her properly. Julie tried to frame Ryan for what Marissa did, which I dont think Kirsten knew about, so I THINK that she decided to take friendship over money but they didnt really write it that way, especially since Kirsten never even knew about it.