I start first, 'kay?

Microsoft  

I think MS will try to get into a more family-friendly market by unveiling a new controller/device that mixes the functionality of both EyeToy (PSEye) and Wii controller, while having enough games to satisfy those that already own Xbox 360. 

• New Xbox 360 Model (Slim) to be announced

• I expect Xbox 360 to be released bundled with a new motion sensing device from 3DV Systems, the creators of ZCam, which MS have recently acquired

• A Halo game from Wingnut Interactive

• Rare to unveil two new games - One for XBL, and one disc-based

• Forza 3 to be in playable form

• Alan Wake to be in playable form (+ release date)

• New game from Bizarre Creations

• New Mistwalker product (Maybe for TGS)

• New Ignition Entertainment exclusive title

• Some sort of Modern Warfare 2 exclusivity - like exclusive beta, exclusive DLC, etc.

• Halo ODST, Mass Effect 2, Splinter Cell Conviction, Lost Planet 2, etc.

Not expecting:

• Versus XIII multiplatform announcement

• You Are In The Movies 2 :)

Sony 

I personally think Sony will target the Hardcore market with PS3 for this Christmas while trying to broadening it's market with PSP, I think Sony will focus most of their E3 presentation on PSP, which I think will disappoint some people. 

Shockers: 

• New PSP announcement (PSP-4000) with its huge upcoming line up

• New Metal Gear for PSP or a Team ICO PSP game/remake.

• Three big new PS3 game announcement - One from Team ICO, another from one of Sony's Europe studios, and one from Sony Japan (maybe an RPG).

Games:

• God of War III demo and a release date for late 2009 (December)

• Uncharted 2 release date and single player demo

• Heavy Rain to be in playble form (+ release date)

• M. A. G. Shadow War beta detail and release date

• Ratchet & Clank: A Crack In Time demo

• GT5 and maybe GT PSP

• Lost Planet 2 or Mass Effect 2 heading to PS3

• Few new unique PSN titles

• Huge PSX library on PSN

• WKC, Ninja Gaiden Sigma 2, Quantum Theory, WarDevil, etc...

Not expecting:

• Wii-mote like controller

• Zone of the Enders 3

Nintendo

I think Nintendo will try to redeem themselves (at least from their fans) by showing many "core" titles, while maintaining the casual market by introducing new mechanics into their games.

Shockers:

• New Zelda for Wii

• N64 game library for DSi

Games: 

• Pikmin 3

• New Donkey Kong or Pokemon Wii

• New Mario or SSB for DS

• F-Zero Wii

• Kingdom Hearts Wii (unlikely, but possible)

• New game from Ignition Entertainment

• New game from Camelot Software Planning

• New game from Intelligent Systems

• Red Steel 2 to release bundled with M+

• Rabbids Go Home, The Conduit, Zelda: Spirit Tracks and more announced games to be in playable form + I expect new Wii colours to be unveiled.

+++ MGS4 Sub... for PS3/Xbox 360/PC

 Now, what do you think will be the highlights of E3 2009?

I dont know about the others but sony sounds about right although i think they could announce ps3 slim,ps2 games and more big ps3 games

It is anyones guess but i get the impression that Sony will be revealing some previous 360 only games getting taken to the PS3 (such as SO4 etc) and i think that they will want to get some more information about price-reduction of the console and possible price-cut!

Lionhead game is going to be revealed.

I'm not expecting F-Zero Wii but I'd love to be wrong. Oh, and...

31 days until the first conference!!!11111

I say one of the big shocking announcements for Sony is that they are going to drop the price on the PS3, but won't do it will the end of their keynote. I still see it happening sometime this year.

DMC 5 exclusivity on 360.

PS3

KHIII(unlikely but possible :P)

Wii

Kid Icarus

Pikmin III

New Zelda

A Zelda spin off made by retro

Matsumo RPG.

only a month to go now untill E3 cant wait :)

all in the list above seems about right

Very unlikely.