In The Chamber of Secretes, it's kind of cute/foreshadow-y to their future relationship that when Hermione is cured and walks into the Great Hall, Ron noticed her first but when they were all running toward each other in excitement, her and Harry hug but her and Ron become very shy and awkward, just shaking hands and smiling. Amirite?
Harry was Hermione's best friend, she felt comfortable hugging him. Her and Ron bickered all the time because they hadn't yet figured out they liked each other- yet they were very emotional seeing each other and had known each other just as long and Harry and Hermione had, so it shouldn't have been awkward, but it was cuz they were in luuuuuurve.
DISCLAIMER: I realize the books are different from the movies. JKR had a hand in the books though, so when I see stuff like this, I think it was her who was responsible for that particular part.