The price would probably pump, because the fear of some guy having 1 million coins would not be there again. Some are worried that whoever satoshi is goes insane and dumps 1 million coins into the market and whatnot. But then again, his coins could be stolen.. so I think it would change nothing. It may be a non event, then again markets can act irrational so who knows. I don't think long term it would change anything.
If that 1 million coin is gone forever, the price of bitcoin will rise at least 5% as Satoshi owns 5% of all the coins.