Yamato, she's still a recent character, but I think she's really cool since she appeared.
Ace, he was lovable character, a kind of Luffy without the stupidity. Still sad about his death even if it was necessary.
Law, I like his BS with Corazon and all.
Whitebeard, he's the reason why Marineford was so good.
Do you consider Bon Clay as a villain ? After all he's done, I consider him as a good guy.
I counted Vivi as a straw hat.