The prophecy could apply to Harry or Neville. Voldemort "chose" Harry, the half-blood, ironically, but it is Neville who is a pure blood.
Plus there is the "Problem of the wands". Even though Voldemort has now taken some of Harry's blood, so that he, LV, has some of what Harry has in his blood that protects him (love, the love his Mother showed by dying for him, and that I also think is the reason Harry is "safe" for a year by staying for some period of time at the Dursley's because Aunt Petunia is connected to Harry by blood (or what we today would call "genes" or family ties), it is clear in "OOTP", Order of the Phoenix, that Harry's and LV' wands, having the same cores, do this gold-stream connection thing.
Big breath.
So, I don't think that Harry has enough hate to kill LV, and since there is this problem of the wands having the same core, and doing that latest curses regurgitation thingy, I think it's going to have to be Neville who kills LV.
Sorry I'm so late to the discussion. I read HBP the first weekend of it's release, and then started re-reading from #1. Just finished and am about to read HBP again. I just had too many questions after HBP and decided that I needed to read all of the books again.
TNT
I don't think Neville will kill Voldemort. He doesn't have the power. At most he might strike a blow that distracts or weakens Voldemort slightly, setting him up for the death strike.
I think that Harry will try to kill Voldemort and fail, possibly due to their wands having the same core, and that Voldemort will think he's won.
And just when all hope is lost, Professor Snape, the greatest of occulumens, will strike, killing Voldemort and avenging Lily's death.
Because Snape loved Lily, which is why telling Voldemort the prophecy that led the Dark Lord to kill James and Lily was the greatest regret of Snape's life.
Only love kills the demon.