E3 is always very exciting, in fact, I can't recall any year being a year where I am like "ehh... E3 this year is gonna blow." No, E3 rocks every year. Here is a brief list as to why E3 will rock THIS year...
Games and potential consoles to look forward to
Assassin's Creed 3 (Native American assassinating British people? Heck yes!)

The Last of Us (A new spin on the post apocalyptic zombie invasion, created by Naughty Dog (did Uncharted series...) Yeah, that's right, it's going to be awesome.)
Tomb Raider (Finally getting that reboot so many fans wanted)
Resident Evil 6 (There has been hype about this game ever since it was announced over a year ago, still no hands on experiences out there, but I think that will change at E3!)
God of War: Ascension (Multiplayer in God of War? Whaaaaa-?)

Halo 4 (The moment all 360/Halo fans have been waiting for, will be revealed at E3 no doubt there will be some hot news on this game.)

Then of course last but not least The Nintendo's new console Wii U and it's games it will have to offer such as the new Super Smash Bros. game, New Super Mario Bros. 2, New Super Mario Bros. Mii, and the mystery title Retro Studios has been working on so fervently. (is it Starfox? Is it Metroid? Or could it possibly even be a
Starfox/Metroid Crossover???!!!??!!?!?!!??!!)
There are many more games, to boot, including but not limited to Vita and 3DS titles (New smash bros. game on 3DS as well as Wii U? Whaaaaa-?)
There are rumors that The Xbox 720 will be revealed at E3 as well as the Playstation 4. However, seeing as how the k'nect is just now getting a go at it, I find it hard to believe they will release another system so soon, unless it has k'nect built in or something. As for the Playstation 4, with Move on the rise, as well as these new 3D glasses technology, AND the potential for the Vita to act as a Wii U-esque type controller, I just don't think we can expect a PS4 reveal.
With so much potential left for the Playstation 3, and the Xbox 360, I just don't think we can expect to see a brand new different console till at least 2014. The Wii U had to be released in order to catch up with the times of HD, online play etc. Therefore, PS3 and 360 still won't really need to compete with much, they just need to focus on upgrading their current systems Move, Vita and K'nect technology, perhaps even an Xbox portable gaming system!!!! But only time will tell...