VideoGamer has posted 4.5 minutes of ninja footage of Diablo III gameplay from the Gamescom 2011 show floor. It’s very good quality, for video of a monitor, and shows some good footage. Remember though, that this is the Blizzcon 2010 demo. It’s not a current version of the game, so all the interfaces, skill systems, etc, are now very different.
You might also enjoy a bunch of photos, plus this video of the Blizzard booth and the huge line for Diablo III, courtesy of German site Diablo-3.net.