Fuu... this could get ugly. Why is it when Misty's involved in a poll, things start to get dodgy?
Oh well, I honestly don't know who to vote for. I like Misty because she's one of my favorite characters, but I've also grown quite fond of Ash as well. Hm... I've always thought of Misty's Ash put-downs not so much as trying to make him upset, but rather more like she tries to make sure that he doesn't get too overconfident. Let's face it, Ash is quite prone to getting over-confident and parading around like some sort of Elite 4 member (the episode with Lorelei is a perfect example). Though don't get me wrong, that's part of why I like his character. ^-^ If I had a friend like that, I'd try to put him in his place once in a while too.
Also, I think the teasing and put-downs also result in Ash trying even harder to prove himself. Without conflict and the pressure to prove he can do it, there's not much drive left to make him give it his all. It wasn't just seen with Misty, but also Gary too. It's like the conversation of "You can't even do ____ Ash!" and the rebuttal of "Oh yeah?!!" This is honestly the sort of thing I think Ash needs in the current series. Someone to propel him to become a better trainer besides the little problems of filler episodes and occasional defeats at leagues and (once in a blue moon) gyms. Though, can't defend her on the slapping. At least she didn't do it as often as Jessie did it to poor James and Meowth. ^^ Eep! I went off on a tangent. >_< My apologies.
Anyway, I think that as a character... oh do I have to pick?? XD Alright, I'll choose Misty. She's headstrong, smart at riddles, hates bugs (like me), and is easily jealous. XD
Oh and Crystal Clair, Misty's eyes are a weird topic of controversy. I swear everyone has a different idea of what they are! They are though, as you said, aqua colored, with both blue-green and that funny aqua green color in them.