I am not a psychic just a gamer with a lot of time on his hands. These are all guess and do not contain any insider knowledge.

Nintendo Press Conference:
I think nintendo will continue to keep up there track record of failure.
1.They will spend 20 minutes on how many DSi's, Ds's and Wii's they sold last year and this year.
2.They will  preach about how they are bringing new experiences to bigger audiences, particularly older and female ones.
3.They will annouce a release window for Zelda Ds game ie Spring 2010.
4.New colors for the DSi.
5.Assure us that Mario team is at work.
6. Announce new Wii (insert stupid title here) game with dumb ass attachement.
7. Remind us that Wii sports Resort is coming soon.
8. Show third party support : Red Steel 2, EA sports games, Harry Potter Movie game. e.t.c.
9.Tease a new Mario game.
10. Proclaim the awesome power of the Wii motion Plus and show games that will support it coming this year.
11. Show new Dsi games but no real dates.

Nintendo Wish:
I would like them to say that they are taking some of there money and hiring new studios to work on new or Old IP's. Seriously bring back 2d metroid for the Dsi.
Also I would like to see WIi virtual console games playable on the DSi.

Sony Press Conference:
I think Sony will be predictable with a few suprises.
1. God of War game playable on the show floor and release date with new trailer.
2. Uncharted 2 scheduled for Fall 2009
3. MAG shown a little.
4. New Ratchet game talked about.
5. 20 minutes of them saying how many PSP's, PS3's and Ps2's they sold. (God for bid they forget about the PS2)
6. Show a new psp that has a release date of no earlier then winter 2009. This new version may be a series 4000 or it could be a new PSP with built in waffle maker.
7.Team Ico game annouced with trailer.
8. PS3 price drop but not really. I think a PS3 slim will be annouced with a bigger hard drive and they will drop the price of current models to get ready for PS3 slim which will come out August or September.
9.New studios added to the PSN movies.
10. Home improvements on the way. I am sure the 8 fans out there will be thrilled.
11. PSP titles Dissidia, Assassin's Creed and Little Big Planet will be annouced.
12. New Twisted Metal Game.

Sony Wish:
Seriously sony give me a reason to love you. Your system has a few interesting things going for it but If I my PS3 was a women she would have left me by now because I hadn't touched her in so long. Annouce an exclusive THIRD PARTY GAME. Kingdom Hearts 3 ,FF7 remake ,anything. Also get with the times of your online service.
Make it not so difficult to play with friends online.

Microsoft Press Conference:
I think when it comes to hardcore gamers they will not disappoint.
1. Halo 3 ODST gameplay trailer with release date.
2. Peter Molyneux game teased with trailer but not shown.
3. Microsoft to show third party support by touching on games like Bioshock 2, Mass Effect 2, Modern Warfare 2, Assassins Creed 2.
4. Forza 3 with Trailer annouced for November,
5. New avatar custumization including possible store where you can buy new items. Yeah for this one I can't wait to have my avatar decked out with a polo shirt that caust me 160 MS points.
6. 1 v.s 100 release date followed by a bunch of casual games.
7. Summer of arcade annouced for July: Will include Marvel V.s Capcom 2 , Teenage mutant Ninja turtles, Golden Eye, Zuma 2 and a few others.
8. They will annouce how many Xbox live users there are.
9. Drop the price of the 360 by 50 dollars.
10. Importance of DLC touched on.
11.Mass Effect 2 will be exclusive.
12. 2nd possible Halo game teased.
13. They will steal a beloved Sony franchise out of Sony.
14. Announce a few JRPG's as well as remind us of Magna Carta 2 and FF13.
15. GTA episode 2 teased

Microsoft Wish:
I'm not expected gold from them but I would like to see one important thing. I would like to see a Zune portable gaming device. I know it is stupid for them to consider breaking into the market of hand helds that is clearly dominated by Nintendo but seriously imagine the ability to play XBLA games like Castle Crashers or TMNT woth a friend while you wait in line for your movie to start. If they marketthe idea right they could come out on top. I could see them making a budle that is expensive but comes with a Zune 2 and 1600 MS points. O well a man can dream.

Overall E3 predictions.

1. Half Life 2 episode 3 annouced/ Portal 2.
2. Beyond Good and evil 2 shown.
3.EA annouces Dead Space 2 and shows al ot of Dead space Extraction.
4. Ea sports talk about "New amazing" features in new titles.
5. Square Enix shows Kingdom Hearts DS and PSP games and brings FF13 japanese demo.
6. Capcom annouce remake of classic game. Please be Mega Man X with better graphics but still 2D.
7.Elder Scrolls 5 possibly.
8. Dead or Alive 5 shown.
9. New Ghost Recon shown.
10. Rare will tease a new game for 360.
11. Namco bandai to show new Naruto, Dragon Ball and other stupid games.
12.Capcom will focus on possible New Street Fighter Characters, Lost planet 2 demo on Xbox live, Dark Void release date and Onimusha game possible annouced.

I wonder how accurate I will be.