Grand theft Auto 5

they y need to time for hype to build up before next fall's release

so this is the perfect time

they will not get enough hype if they just announce at E3 next year as the release period would be very close

Elder Scrolls V

Although I wouldn't want it to be revealed at Spike VGA.

I want that game so badly!

Random guesses at what we will see. Not a prediction, just a few titles that I think could be possible.

Halo Remake.
Halo Wars 2
Age of Empires 4
Uncharted 3
Batman Arkham City Footage.
Agent trailer
Grand Theft Auto 5
Starhawk.
Zelda Skyward Sword (Seriously!)
With how Demon's Souls did over in the States, I also think we will see "Project Dark". 
Duke Nukem Forever.
Fallout Online.

Me too!!!!!!!

And I would gladly buy and play it for many, many hours in your memory.