Photo realism isn't very far off at this point. The graphics engines that people can work in now are insane and that dream of playing video games that are nearly indistinguishable from reality are getting clearer in sight.
Case and point, look at these pictures made in the upcoming Need for Speed engine posted up on Speed Hunters. Ghost Games created this render of a car in their game from a photograph. Now, I'm sure if we saw this in motion it would be much easier, but it is pretty hard to distinguish the two here. The results are pretty stellar.
Take a look:
Need for Speed is out Novemeber 3rd.