I think Hermione and Ron make the best couple, since it's so obvious that they are going to end up together, but I also think that Parvati is a likely canditate for Harry. I always thought that the person right for Harry should always have been there since the first book so their like for each other can mature and develop. (Don't ask me why, I don't know. I just always thought that because it won't seem well to me if it's a newer character.)