First and foremost, we expect Sony to reveal for the first time what the PlayStation 4 actually looks like. The launch event in New York in February focused a lot on the vision for the console; what it would be capable of and so on. But the box itself wasn't shown. As promised by this teaser trailer from April, that'll be righted at E3.
As for games, we can expect more about first-party titles like Infamous: Second Son, Killzone: Shadow Falls, DriveClub, Knack and that weird whatever it was by Media Molecule. There'll also be more on upcoming PS3 games like Beyond: Two Souls and Rain. Naughty Dog's The Last of Us, set to launch on 14 June, might also get one big last publicity push.
So, we'll see the console and some more games, but we'll probably also get some more of the "vision" talk that Sony gave in February. At the D11 conference, reported by The Verge, CEO Kaz Hirai has said already that the console will be more games driven than Microsoft's Xbox One, but not everyone is convinced that's the best strategy. Given the expected long shelf life of next-gen consoles, Sony needs to drum up some kind of long-term monetisation strategy, a way of getting consumers to continually but things through the PS4 once they own the console. Microsoft is consolidating all its services into the One and bringing in new revenue streams in the shape of cable subscriptions; if Sony wants to stay competitive, something similar will have to be implemented into the PlayStation 4. Expect to hear about this at E3.
The Sony keynote kicks off at 2am GMT. IBTimes UK will be covering it live and reporting on all the big announcements as they happen.