I've read the four twice through, I've read the first three, I believe, four times. I figure once Martin announces a date for release of DwD I'll start reading the whole series again and that should get me pretty close to release date.
You are pretty much meant to hate Joffery, he is one of those characters that is just twisted to the point that he doesn't inspire any compassion. Even Cersei you get a chance to at least appreciate her situation, understand her goals, so while you may despise her, there is a little pity there as well.
I like Theon. I liked him the first time through, and somewhat despised Balon, but I liked Theon even more the second time through. He is torn between two worlds, desparately trying to seek the approval of his father, live up to his heritage, but at the same time he was genuinely friends with Robb and is having to find out that loyalty to friends and loyalty to famly can conflict and that maybe finding his own way through those entanglements is the only way.
My favorite characters are Jon and Tyrion... probably the two best examples of intelligence and honor in the series. I do quite like some of the less savory characters (Bronn), as well as a great appreciation for the Dornes we have been introduced to. I'm going to be very happy to read more about them at some point in the series (like Quentyn's quest).