According to Next Gen, E3 is history:

Senior industry sources have revealed to Next-Gen.Biz that the E3 industry event, in its present form, has been cancelled for next year and the foreseeable future.

The Entertainment Software Association (ESA) shindig has been a staple of game industry life since the mid-1990s. However, we understand the larger exhibitors have jointly decided that the costs of the event do not justify the returns, generally measured in media exposure.

Publishers believe the multi-million dollar budgets would be better spent on more company-focused events that bring attention to their own product lines rather than the industry as a whole.

A consequence of industry consolidation? A similar thing happened to the ECTS in London: it went from two shows, to one show, to a confusing mess of competing events that was then replaced in importance by the Games Convention in Leipzig.

I've never been to an E3. Everyone always tells me they're terrible.

Update: Some commentary from Kim Pallister.