http://www.e3expo.com/Should be a most excellent show. We've the successor to the Wii to not only be on display but also be playable. Also Sony's next foray in the portable gaming market, rumored to be named Vita, should also be at the show and should also be well into its development (likely a finished model or close to it).
Last year's E3 was plagued by motion gaming devices. Also the 3DS was yet another gimmick that has been a large disappointment.
E3 always offers surprises and this year should be no different. I think Nintendo will steal the show with Project Cafe aka WiiHD. The WiiHD is rumored to have a more standard controller but with a touch screen built in. In my opinion this is quite genius because the IPod Touch has been an impressive gaming device thanks to its touch features and gyroscope. Surely Nintendo has asked themselves why they weren't the ones to have created Doodle Jump or Angry Birds. I'm really interested in how they will interface the console with the controller. Also with the more standard controller we return to the more familiar form of gaming. We'll be playing the likes of Mario and Zelda in high definition for the first time with the touch screen controller also adding new experiences.
Nintendo also has the 3DS which has potential that hasn't yet been realized. I feel they launched the handheld console too early. Hopefully Nintendo will have some amazing titles to reveal for the 3DS.