I really don't like Luna so I hope she doesn't get in the way of R/H or H/G. And she better stay away from Neville too!
Er, anyways...I'm not good with predictions, but I agree with what has been said so far. I think Ron will be Quidditch Captain and Head Boy, Ginny will make the Quidditch team and Harry will confide in her more and separate himself from Ron and Hermione, Krum will make a return (not to sure about Fleur. And I don't think Ron will get another "love interest" just b/c that boy is too hung up on our girl Hermione and I can't really see him having eyes for anyone else but her. And Hermione won't have a "love interest" either, unless you count Krum, which we all know is just a friend to Mione. And as much as I want it to be true, I don't think that Authur will become Minister of Magic. I dunno, I just kinda see that as a stretch, since he doesn't seem to be too popular with the Ministry right now (esp with all the evil influences).