Blizzard has posted a Launch Day Preparation Guide over on their Battle.net blog to help all of us be ready for the launch of Diablo III. Just a reminder that The Americas (U.S., Canada, Latin America, Australia, New Zealand, and South East Asia) servers open at: 12:01 a.m. PDT, May 15. It's important to understand what that means for your timezone so you don't lash out on forums for no reason.
In addition, if you would like a refresher on the Diablo Lore I would have to highly recommend ZealousDemon's Diablo Story series on Youtube. If you want an in depth look at Diablo III's mechanics, especially how they differ from previous games in the series, look no further than Dontinquire's amazing post on the Diablo III forums.
The writers here at The Gaming Nook are rather excited about the release of Diablo III so you can expect to see some more content concerning the game very soon.
Diablo III: Standard Edition