I've been re-reading these lately for the first time since... Well, since Deathly Hallows came out back in '07, I think. They've been quite enjoyable reading. I'm disappointed to see Chamber of Secrets with just one vote tbh. If not the best book in the series, I've found it to be at least the most abundantly fun. I'd say my favourite is either that or Goblet of Fire. Order of the Phoenix is probably third, and is also probably the closest that any of the books come to being maximalist fiction. Despite being one of the better films, I strangely found POA to be one of the lesser enjoyable books.