I'm a fan of speed runs because they can be impressive, entertaining, and because of that the focus is less on chat and more on the streamer.
http://www.twitch.tv/team/sda
As mentioned above, cnotbusch is really cool and chill. MvG is also good, and pretty interactive. Personally I like smaller streams because you can interact more and the trolling is not nearly that bad (I've had a few run ins with some keyboard warriors, but less so in those types of streams.) Plus, it helps the streamer.