Arlong's Arc was really good. Very bloody and emotional, but fell victim to the "main-hero-is-unavailable-until-the-very-last-second" disease.
I had JUST finished the dragon arc, which was a bit subpar. Right now they've been on the grand line for a few episodes and I'm on the Baroque arc right now, which is turning out pretty well. Luffy's rage toward Zoro after that "certain event" when they were at Whisky seemed a bit out of place though. Luffy doesn't seem the type to go into a blind rage and completely ignore what his own friend has to say.
Still, I'm on a roll. I was in the middle of another anime before watching this and I had some more episodes to dwnload and finish, but One Piece completely took over, and for good reason.
However, during a quick trip to wiki, I discovered a spoiler on accident about Usopp that pissed me off.
But as far as favorite character, mine is Luffy. Villain is definately Buggy the Clown. I'm glad he keeps coming back.
This thing is sticky, and I don't like it. I don't appreciate it.