I think that Harry's victory over Voldemort will be based strongly on his feelings of love for friends and family. This will make him continue his relationship with Ginny, and change his mind about Ron and Hermione working with him to find Voldemort, and it will play a role in the final battle with Voldemort.
OK, it's not a revolutionary prediction, but now for the explanation of why this prediction is an application of Torah thought.
Throughout the first six books we've read of Dumbeldore's belief that love is the the most powerful magic. Early in the series this seems to be a very abstact concept, such as in Harry Potter and the Order of the Phoenix when Voldemort tries to magically enter Harry's brain but is unable to do so when Harry thinks about his love for his father-figure Serius. But in Harry Potter and the Half-Blood Price (chapter 23) the magical power of love is given a more concrete meaning:
[Dumbelore said:] It will take uncommon skill and power to kill a wizard like Voldemort....
"But I haven't got uncommon skill and power," said Harry, before he could stop himself.
"Yes, you have," said Dumbeldore firmly. "You have a power that Voldemort has never had. You can ---"
"I know!" said Harry impatiently. "I can love!" It was only with difficulty that he stopped himself from adding "Big Deal!"
"Yes, Harry, you can love," said Dumbeldore, who looked as though he knew perfectly well what Harry had just refrained from saying. "Which, given everything that has happened to you, is a great and remarkable thing. You are still yoo young to understand how unusual you are, Harry."
"It is essential that you understand this!" said Dumbeldore, standing up and striding about the room, his glittering robes swooshing in his wake. Harry had never seen him so agitated... "It is Voldemort's fault that you were able to see into his thoughts, his ambitions, ... and yet, Harry, despite your priviledged insight into Voldemort's world... you have never been seduced by the Dark Arts, never, even for a second, shown the slightest desire to become one of Voldemort's followers!"
"Of course I haven't!" said Harry indignantly. "He killed my Mum and Dad!"
"You are protected, in short, by your ability to love!" said Dumbeldore loudly. "The only protection that can possibly work against the lure of power like Voldemorts! In spite of all the temptation you have endured, all the suffering, you remain pure of heart...."
"But sir," said Harry, making valiant efforts not to sound argumentative, "it all comes to the same thing, doesn't it? I've got to try to kill him, or---"
"Got to?" said Dumbelore. "Of course you've got to! But not because of the prophecy! Because you, yourself, will never rest until you've tried! ... Imagine, please, just for a moment, that you had never heard that prophecy! How would you feel about Voldemort now? Think!"
Harry ... thought of his mother, his father, and Sirius... A flame seemed to leap inside his chest, searing his throat.
"I'd want him finished," said Harry quickly. "And I'd want to do it."
... He understood what Dumbeldore had been trying to tell him. It was, he thought, the difference between being dragged into the arena to face a battle to teh death and walking into the arena with your head held high... Dumbeldore knew -- and so do I, and so did my parents -- that there was all the difference in the world.
We see here that Harry's power of love is a concrete power that gives him magical motivation and strength against the black magic of Voldemort.
In the Torah this power of love, power based on relationship and based on emotion, is the power of Joseph. Joseph is the dreamer. Joseph is the only man in the Torah to be described in terms of his good looks (Gen 39:6, compare with 29:17, 24:16). Joseph is appointed leader of Egypt in a role that seems to be much more about the image of leadership than about management (Gen 41:42-43). And Joseph's blessing from his father is focused on his relationships (Gen 49:22).
On the other hand, the power of the strong rational and intellectual leader is Judah (eg Gen 44:18). Judah took charge of the plan to sell Joseph into slavery (Gen 37:26). And from Judah ultimately came King David and the royal line of kings. Judah was the source of Jewish leadership.
But, as an interesting analogue to the Harry Potter story quoted above, Judah did not have the power to withstand strong temptation from Tamar (Gen 38:15-16) while Joseph DID have the power to withstand similar temptations from Potifar's wife (Gen 39:12). Judah lost his Jewish purity in dealings with non-Jewish tribes (Gen 38:1, Rashi there) while Joseph fought to maintain Jewish seperation in Egypt (Gen 46:34).
However, and the paradigm of leadership by emotion and love and relationship, Joseph is held to a tremendously high standard. Joseph's relationships HAD to be altruistic and for the sake of the greater good. A tiny bit is self-interest (Gen 40:14) caused Joseph to be held in prison for two extra years (Gen 41:1, Rashi). If someone is going to be driven by love and emotion, it must be pure. Emotion of self-interest will not succeed.
Ultimately, the salvation of the Jews in Egypt started with Joseph, and only after that was Judah the leader. And ultimately we are told by the Prophets that Jewish salvation will come from the joining of forces between Joseph and Judah. "Take a stick, and write on it 'for Judah,' ... then take another stick and write on it 'for Joseph,' ... Join them together into one stick, so that they are one in your hand... behold, I will take the children of Israel from among the nations.. and will gather them on every side, and bring them to their own land" (Ezekiel 37:16-21, Haftara of VaYigash).
So we've seen strong analogues between Harry Potter's magical power of love and the power of emotion-based leadership of Joseph in the Torah. As we read about Harry's victory over Voldemort, which I predict will be based strongly on this power of love, we can also hope and pray for Jewish leadership to find the right balance between love (which needs to be purely altruistic, not self-interested) and rational strong leadership, to bring us the salvation we pray for and an end to the exile we remember on Tisha B'Av next week.
A lot of the ideas written here are based on the Torah thoughts of Rav Ahron Levitansky and Rav Matis Weinberg.