Obviously there's going to be a saturation level of Diablo 3 news in the near future, so forgive me if I've duplicated anything here in this collection of screenshots and videos.
First off, GamersHell has a streaming Witch Doctor combat trailer , Barbarian Attack trailer, two other videos and 85 screenshots available on their Diablo 3 game page.
PCGames has 22 of these screens in larger format here.
Gametrailers has all of the above trailers and more here.
Finally, here's a link to Gamespot's video library, where you can find some panel discussion trailers and a slew of interview and demonstration videos from the WWI, including this one on Lore and Environmental Art with Leonard Boyarsky.