[SmartBlondeGPhB]

Ok, I had a thought this morning in the shower (yes, that's where I do my best thinking).

I agree that DD was stalling Draco until Snape got there.

Dumbledore said in CoS that "I will never really be gone as long as there are people here who are still loyal". What better way to GUARANTEE loyalty to him (i.e., he'll never be gone) than to make sure that the person who kills him (or appears to have in case it was the poison from the horcrux that really did it) is the one most hated by Harry and everyone else?

And yes, DD is definitely dead for the reasons stated above.