Okay, so I was so excited when Harry and Ginny finally got together in the sixth book and then super bummed when they broke up. I can understand Harry's reasoning behind it but this is what I have concluded since reading the books so far...
Dumbledore had always told Harry that it was love that protected Harry all this time. And he had also just told him that if it wasn't for the fact that he only went after Harry when he was a baby based on what he had heard from the first half of the prophecy. And in failing to kill Harry he had passed on some of his powers to him. Now, as far as I can tell, Harry could have very well made the choice to fight on the side of evil but he didn't. It was love for his parents and all of those that had been taken away from him at the hands of Lord Voldemort that has spurred his need for revenge, not just for the sake of power and evil. And that in having that love (that which Lord Voldemort will never be able to comprehend) it only makes him stronger.
So am I right to conclude that it would only make sense for Harry and Ginny to reunite in the sixth book? Because, with how strong the love is that they feel for each other, wouldn't that just make Harry stronger? One of the main reasons that I believe this to be true is because... at the end of the sixth book when everyone is standing around Dumbledore's body at the bottom of the Astronomy tower, it was only Ginny that was able to bring Harry out of the trance and refusal to leave Dumbledore's side that he was in.
Therefore, it would only make sense to me that they reunite and fight together against Voldemort.

(Maybe they will even get married? Who knows... what does everybody else think about all of this?)