If you ask me, Ron and Hermione are like siblings. Like my brother and I, even if we fight, we still get along. I agree with Sneh. There will be some bizarre twist. We've all read the books and we know Rowling doesn't give hints are tricky. So why would she make Ron and Hermione end up together? Its just too obvious!
I don't want to dissapoint anyone, but I think one person in the Golden Trio will be dead at the end of the series. We know that either Harry will die or Voldemort. We also know that Voldemort knows Ron and Hermione are Harry's best friends. He even attacked Mr. Weasley. I think Voldemort will kidnap either Ron or Hermione to lure Harry.
If Harry dies, Ron and Hermione will be together. Otherwise, I think Harry and Hermione will be together.