Blizzard has updated the official Battle.net website with an official (I used this word twice, forgive me) image of Diablo 3's box art, perhaps as an indicator for the game's upcoming open beta which looms closer on the horizon.
It's got numerous fans of the game hoping that it means the beta will be released at some point in the next couple of weeks, but I'm not holding my breath.
If anything, it just means that Blizzard's plans to release Diablo III are that much closer, and that we can expect to see more information–both about the Beta, and the game itself–released as the date nears.
Diablo 3 will be released on both the PC and Mac. Blizzard has not announced any plans to bring the game to either the PlayStation 3 or Xbox 360 consoles.