I've read the illustrated edition, and it's so beautiful! I've always loved the story, but these drawings are amazing.
In 'the Chamber of Secrets' we start to know more about Voldemort, and it raises questions for Harry about his own identity. He realised the things he has in common with Voldemort, and begins to wonder if he will be a dark wizard himself, if he will go towards evil too.
Then Dumbledore comes with his best line of this book (maybe the entire series): It is our choices Harry, that show us who we are, far more than than our abilities
I loved the part where Harry was taken to the Weasly's house. Ron is ashamed of his home, but Harry loves it.
Aragog gives me nightmares though.