I've been having a lot of fun using a Panorama P1 and a LaunchPad to control Bitwig. I love that you can switch the LaunchPad between horizontal and vertical arrangement of clips to match the Arrangement view or the Mixer View. I also love the use of button LEDs as signal level indicators.
These guys have some really cool ideas on how to to work with controllers. Not only for the obvious application of controlling stuff but also for giving the user critical information about the state of the project/track/whatever you are currently controlling.