If you follow the Dontronics newsletter you would know that Scenix (Ubicom) had a design contest for using a TV screen as a cheap alternative to LCD displays.
Video is definitely a candidate for the C420. I have always needed more speed when trying to accomplish several tasks with the same processor. Like controlling 9 stepper motors at once. When more than 3 motors were running, their movement became jerky. More speed can sometimes mean more medium speed stuff running simultaneously.