I've been using Adobe Idea's for quick story boards and blocking.
Is super fast since I also take my scouting pictures using the ipad.
Basically I take a picture with the ipad, name the picture, then with the pen i draw over the picture to get my blocking and flow right.
Since all my scenes are done with motion control, speeds up that work flow a lot (since it allows me to figure out the system placements).
Here's a quick example: