Saw an interesting theory in another forum with regards to love and sacrifice. Something similar to the love blocking spell Karma Police and I were discussing earlier. For lack of a better term, I'll call this the Anti-Horcrux theory and reiterate once more that this isn't my theory. It does however take a lot of the thoughts I've been having and put them together nicely.
"We know that a horcrux is created after committing the most evil act: killing another human. The books say that every time a murder is committed, the soul is torn. Creating a horcrux is encasing the bit of torn soul into an object outside of the body.
So the opposite action would have to be the most loving act that someone can commit, and it would combine two souls. What would that act be? All I can think of is:
Sacrificing yourself for a loved one- dying for them
Creating a new life- giving birth to a child
Just having love for someone
Dumbledore reiterates throughout the series that Tom Riddle has never understood love. He says Harry's weapon, his advantage over Voldemort, is his ability to love and be loved. That's supposed to be what allows him to defeat Voldemort. You could argue that it's simpler. Love may just be what drives Harry to go after Voldemort in the first place, but how is that something that Voldemort doesn't understand?
Couldn't loving someone do the opposite of a horcrux, then? Join two souls. If that's true it must happen all the time, naturally. It's like how you never really die, because you live through your loved ones. Voldemort would have overlooked this.
It would be kind of neat if say 7 (or 6, if you want 7 pieces total) people died loving Harry. The final battle would be 1/7 of a soul vs. a soul 7x reinforced. Is that significant? It's not like their SOULS are battling physically, but it would give Harry protection and strength (as we've already seen).
1. Lily
2. James
3. Sirius
4. Dumbledore
I've said earlier that I think Ginny might die and this only furthers that thought. As much as I don't want to see it happen, I think it'll be Ginny and/or another adult figure we've known through all the books who dies. There is also a distinct possibility that Wormtail repays his "life debt" to Harry thus strengthening Harry's soul.
Something else I came across was the Japanese translation of the book title:
While I don't necessarily think it's a spoiler I'll attempt to use spoiler tags for those who choose not to know translated book titles for fear that it may reveal information. If you deem it not to be a spoiler and want to discuss further, without the use of spoiler tags, just let me know and I'll edit the post to remove the tags.