Five years later, and this is the state of the art:
Which is, I totally admit, a very neat tech demo. But it's not "there" yet. The FOV is too small, and you can see the real world through it. Although, to be fair, most of the time the real world isn't _that_ distracting, you're definitely not going to be able to "see Victorian gas lamps in place of normal lights" or "have a real Coke can that you want to turn into an AR Pepsi can by drawing a Pepsi logo over the Coke logo".
Ah well, I'll make a note to come back in five years time and see where we are then!
Original post on Dreamwidth - there are comments there.