Well, something else to consider...
What if Voldemort has no intention of killing Harry?.
Obviously, the attack on Harry was the last that Voldemort performed before he was "destroyed". Remember that Voldemort had to killl 7 people in order to fully divide his soul and preserve parts of himself. It's safe to say that he had already killed at least 5 before Harry's parents, who would have been & 6 and 7. What if the spell he cast on Harry was NOT a killing curse, but instead, a spell that embedded that last shred of his soul into the scar on Harry's forehead?.
What if Voldemort has no intention of killing Harry?. What if he plans to take Harry's body?. Remember in HBP, someone mentions Voldemort "using Potter's blood to become immortal". I don't remember that happening in the previous books.
I wouldn't be surprised in the least if that's what it turned out to be.
Also, even though Snape killed Dumbledore, I hadn't seen the angle of Dumbledore pleading for him to do so, until I read Stamen's post, and it makes sense.
Part of me still wants to give Snape the benefit of the doubt. Dumbledore trusted him after all. However, JK foreshadowed this possibility in one of Harry's early meetings with Dumbledore in HBP. Dumbledore says something to the effect of being "more clever than most" but that makes his mistakes much bigger. So, was he truly misguided in trusting Snape?, was that one of his bigger mistakes?.
Also, it seems odd to me that someone like Dumbledore (even weakened) would be unable to cast a spell minus a wand to disarm a little $hit like Malfoy. I hope Dumbledore wasn't going the Obi Wan Kenobi route, that would seem cheap. It was bad enough that Harry went the Peter Parker route at the end with Ginny.