Rob-
It is actually easy to miss, but once you catch it, it's pretty obvious:
Warning: Spoiler! (Click to show)Early in the film, Deckard tells Rachel about her implanted memories; he specifically mentions an incident that she never told anyone about.
Later, Deckard is dreaming of a unicorn
At the end, Deckard finds Gaff's orgami unicorn, and he realizes that Gaff knew that the unicorn was an implanted vision, and that he himself is a replicant.
At any rate, I think both implications work. If Deckard is human, you have the whole idea of the replicants acting more human than a human does. If Deckard is a replicant, though, the irony is that he is hunting down his own kind, and also seems to have been designed exactly for that purpose.
I like both the OV and the DC, but I think I prefer the DC. The voiceover never really bothered me, until I saw the DC, and I realized how over-explanatory the OV had been. I absolutely love the "Tears in Rain" scene without the final voiceover. I imagine it wasn't intended to be that long, but the uninterrupted sound of the rain mixed with Vangelis' score is just haunting.
I am still holding out hope for an Ultimate Edition, but for now, I am very glad Warner is bringing this out as a 2-disc SE. I will certainly be getting it.