DualBoard, leave the mouse behind. Besides all the great features of annotating on screenshots and video recording presentations, the most basic feature is often overlooked.
Because the interactive whiteboard's pens also act like a mouse, teachers can walk away from their desk and run their computer right from the board. This puts the teacher squarely back in front of the class. it also adds an element of "cool" as the teacher appears to manipulate screen images with just the touch of a pen.
And then, for those adventurous types, try handing the pen off to a student. There may be a momentary learning curve as they realize the controls are not as sensitive. But remember, never allow a student to use your computer without supervision and permission. Even though DualBoards are interactive, the teacher must remain in control.