From the Press Conference we know that there are three characters whose names are shrouded in mystery. Naomie Harris has stated she is to be called "Eve". But is this a code name for Miss Moneypenny out in the field? One of the main set pieces could well be a chase on foot throughout London's Whitehall area.
The plot talks of personal cost. As some of the movie is being shot in Scotland, could Albert Finney be playing Bond's Dad, Andrew Bond who was from Glencoe according to Fleming. Maybe he faked his death? Sam Mendes said that Skyfall is not based upon a Fleming property, so perhaps they've decided to change Bond's mythology somehow.
Whatever the full details of the plot are, Skyfall is sure to be an entertaining movie.