Probably Microsoft. They needs a high-profile presentation to show and convince people that the xbox is still a viable platform. They need to make a splash with high-profile games, preferably exclusives.
Nintendo has lacked BIG games this year, but by no means a drought(at least in my opinion). But i don't think Nintendo is dependent on E3 to show their big games
As for Sony, if they didn't show up at E3 it wouldn't hurt them at all
Nothing to see here, move along