Olaf or gangplank top

This isn't even an option, Gangplank.

Olaf is a terrible champion. He's sort of like Warwick: He gets stronger as he gets lower on health. But he has very little way of gaining that health back.

I really dislike Olaf. :p

Gangplank has A LOT of hidden skill to him but he's very rewarding if you can master him. And you can pick up so many cheesy, free kills with your global ultimate. :)

I guess this question really comes down to your play style.

Olaf is a very "up in yo face" type of champion. Gangplank is more versatile: He can sit back and let the cheddar roll in if he wants to.