This is a simple question. Who will win E3? There's a lot of hype surrounding everything, and hopefully all of the companies pull a few suprises. 

um theres already a thread about this

Who knows?

I think, Nintendo has a pretty great Lineup this year. If they show 2 or 3 new, great titles (maybe some unexpected like F-Zero etc.), they will have my vote.
Let's wait for Sony and Microsoft to show what they have. For me, the absence of FFXV and KH3 is a big disappointment. On the other hand: MGS:V looks to be an awesome game.
Microsoft has Sunset Overdrive and Quantum Break.. i don't know what to think of those titles at the moment but Sunset Overdrive looks interesting. We will see..
(btw: Nintendo got my vote)

Sega

Nintendo!

It depends what you mean by 'Win E3'. If you mean who will have the best games regardless of sales potential then it will be entirely subjective and in the vast majority of cases confirmation bias will ensure that everyone who expected/wanted their preferred company to win, will believe they won. This is especially true where niche titles such as the Last Guardian could be shown, leading fans of such games feeling as though a certain company 'won' E3.

If you mean who will best leverage 'E3' as an opportunity to promote future console sales, this is almost certainly going to be Microsoft of Nintendo. Quite simple, this is because Sony is currently outselling those two companies, often combined, despite an almost complete lack of high-budget, high visibility AAA content. In other words, the only place Sony has to go at this E3 is down. Whereas even a viable attempt at levelling the playing field would represent an E3 'won' for Microsoft or Nintendo.

If you mean on these forums? It will go by userbase - in line with the aforementioned confirmation bias. Sony > Nintendo > Microsoft - irrespective of what is actually shown.

Microsoft if they stay true and only show games. i feel like Sony conference i already now what to expect yes ms has shown games but other then horizon we knew those where going to be there for sure

and i don't really follow Nintendo but they could have a good show

Simply Nintendo. Smash Bros, Zelda, Hyrule Warriors, Bayonetta, X, Pokemon, Shin Megami Tensai X Fire Emblem, Yarn Yoshi, potential Mario Kart DLC, all the other unannounced games. It's clear whose got this in the bag imo.

1/2 the battle is showing up - so that makes it hard for Nintendo considering thier lack of press event and Iwata not making it. I hope this IS the time Nintendo delivers or even beats expectations but so far they have not done so in key directs, previous e3 s etc. so until they do deliver its hard to think they won't be a letdown some how
With all the games they can announce and discuss it sems it may be difficult for them to under perform but they seem to find a way. We will see