Well Nintendo are focusing on Zelda U/NX this year, so all the news from that will likely have people abuzz. I'm kind of hoping for a "surprise" announcement for the NX (only because they haven't really said much about it or E3). As for Microsoft and Sony themselves, maybe more on HoloLens and PSVR? I can't see them having a whole bunch to reveal on their own tbh. I'm looking forward to more on Dishonored 2 though, and maybe the next Destiny expansion which is rumoured to be revealed. Overall, I'm personally going to say Nintendo, simply because I know the Zelda news is going to have me jumping out of my seat like the 7 year old boy I am inside.