Someone elsewhere suggested that Voldemort wants Harry to kill the Death Eaters, who are obviously too stupid to live if they missed that trick.

Theory: Voldemort has let Harry keep his wand because he intends Harry to do something with it. In story we have plenty of evidence that you can't "mess with time". Think of prophecies as messages from the future instead of predictions and it's obvious. Voldemort knows this first hand(and maybe Harry will figure it out) so instead of trying to foil the prophecy or actively trying to force the prophecy to play out in the most beneficial way he can imagine, like he did with his first encounter with a prophecy, he is trying to make it so that prophecy two cannot play out in any other way except the way he wants it to.

"He didn't understand why Voldemort was not just killing him. There seemed to be only a single line leading into the future, and it was Voldemort's chosen line"

So, the question we should be asking ourselves is this: How would you make these prophecies come true in the best possible way? If you were Voldie? If you were Harry?

"HE IS HERE. THE ONE WHO WILL TEAR APART THE VERY STARS IN HEAVEN. HE IS HERE. HE IS THE END OF THE WORLD."

"The one with the power to vanquish the Dark Lord approaches... born to those who have thrice defied him, born as the seventh month dies...And the Dark Lord shall mark him as his equal, But he shall have power the Dark Lord knows not... and either must destroy all but a remnant of the other, for those two different spirits cannot exist in the same world.

Two spirits cannot exist in the same world implies multiple worlds, only destroy one of them? Move one of them to another world? Would you try to set up a future where Harry "tears apart the stars in the heavens" as a fuel source to power an advanced civilization? Could the "end of the world" refer to the purposes of the world? The end for which it was created(Atlanteans?). Either that Harry is that end or that he will accomplish it?

Assuming that it is true that Voldie is trying to control the prophecy and not foil it, what do we know about what he intends, or expects to happen next?

*Some move that the unbreakable vow constrains Harry to do

*Hermione will escape?(His inside joke laughter)

*Require's Harry to have a wand

*He expects Harry to figure it out given available evidence

Anything else?

An important question to ask: What possible fulfillment interpretation of the prophecy(ies)(Does Voldemort really believe the first one already fulfilled or is he trying to accomplish both?) would Harry's actions be constrained towards by the unbreakable oath and the other conditions Voldemort has set up for Harry?

Maybe Harry just accepts that he is destined to destroy the world no matter what and since he doesn't have the power to do it now he MUST survive his present predicament and become much more powerful than he currently is so he resolves to return to this point in time when he achieves ultimate power. So kick butt Harry from the future is about to show up and knock some heads.