I don't know, but I think the result of the road race may play a part. If Cavendish wins there, not only is it likely that Wiggins will have spent energy aiding him, but the pressure on Wiggins to deliver a gold for cycling at a home Olympics is off. His season couldn't have been much better than it has been, so I'm really not sure how motivated he's going to be, unless he is the only road cycling medal hope for Britain.
Fabian, on the other hand, strikes me as a man with a point to prove. His stint in yellow rescued a disappointing season (Strade Bianche notwithstanding), but for a rider of his quality would really be wanting far more from the year.
Sadly for Tony Martin, it doesn't look like he's going to be back to his best for this year at least.
I think Cancellara and Wiggins will take gold and silver, but in what order I'm not too sure. I think my tip for bronze would be Chavanel. He has had a really good season and looked strong in the TdF TTs.