Im gonna have to say Nintendo. New handheld, Zelda and Super Mario Galaxy 2. That's going to be
an amazing event for them, it'll be good for ALL 3 of them actually.
Im already starting to save up for3DS through Lockerz.. haha so I'll easily be able to get it for free when it comes out. Message me if you want a free invite, just leave me your e-mail address.

i think nintendo has the upper hand going into the show followed by microsoft then sony, but then thats the whole point of the show, is that we havn't seen any of the megaton bombshells yet, personally i think everyone will have a great show this year,(not trying to osund corny but its true).

Nintendo:
zelda wii
metroid other m
pikmin
vitality
Pokemon 5th gen
3DS
New games
Epic mickey


Microsoft:
Natal
more 3rd party exclusives
Reach
gears 3
fable 3
mass effect 3 teaser
portal 2

Sony:
Gran turismo 5
last gaurdian
versus 13 + ff14
Agent
maybe one more huge 3rd party exclusive
jaffe game
killzone 3
Move stuff
Socom 4 beta prolly

Overall itl be hard for the big game sites to call a winner on this one, unless some massive gigatons are dropped either way like gta 5 exclusive to one of the hd platforms, or Kh3 on wii, ff7 remake, iuno gonna be a great year for gamers.

Sony

Move+3D+GT5+The Last Guardian+Agent+Eat.Sleep.Play Game+Demon's Souls 2+Killzone 3+Resistance 3+SOCOM 4+Syphon Filter 5+Motorstorm 3+Media Molecule Game+FFXIV+FFVSXIII+Random PSN Games+PSN Premium+Megaton Announcements (PSP2?)

Based on sales think it is safe to say nobody really gives a monkies about Resistance 3, Killzone 3, Motorstorm 3, LittlebigPlanet 2 etc etc, in the realms of big games they are nowhere near it. Feck Halo 3 sold more then all their prequels combined!

No megaton announcements either. Sony are 3rd in sales, nobody is going to jump ship to them and miss out on 30m+ sales, especially big franchises in america where 360 is at double the sales of the PS3.
Think about it. 12 months ago Sony lost two of its biggest franchises in Metal Gear Solid and Final Fantasy.

Where as it is possible Microsoft could get exclusivity to some franchises such as GTA, they did it before, they can do it again.
Last year Sony had their best E3 showing for years with the pruce cut and new model.
This year will see MS do the same thing.

E3 2010 in my opinion will probably be the last big one this gen.

Geez, no one really knows. Nintendo is set for a good E3 with the 3DS and Zelda, but Microsoft too with Fable III and Natal...

Sony, dunno.

actual ps3 slim model and price drop.!!!

Sony because they might take out ff9 on the ps3 around e3 which is a bonus,I swear if they announce ps2 classics then its a automatic win