Its definitly an xbox announcement not a gaystation announcement
it could be mass effect 3 but i tink that will be out sooner than 2013 so my best guess is a new halo game probably halo 4
or even...
The Elder Scrolls 5
the new game in the vga trailer is ME 3 if you look closer like it tells you to you can see the normandy and maybe part of a reaper
the normandy is in it and so is part of a reaper the guy is a new recruit and only part of MASS EFFECT 3 is set in london
If you look very closely you can see the normandy making its way over in the top left corner and the tenticle leg things on the bottom of the reapers dangling a bit further in front and to right of it
HALO 4 launch game for the nextbox but i think the game will be the one from crytek that was shown at E3 becuase that has dissapeared since