I'm going to buck the trend here and say the perceptual equivalent of human vision is best approximated by a slightly long lens ...maybe 80mm?

As has been said, the degree of critical sharp focus of the eyes is very narrow and that's why they always flit about to create a collective focused impression of a scene. But there's a limit to the the degree we shift the eyes before the natural inclination is to move the head. I think that (disinclination to move the head) defines the distance from which we normally view photos and, for me, translates into a slightly long perspective of the actual scene.