Jared Padalecki, who played Sam Winchester on the recent Scoobynatural crossover episode, stated in a recent interview that he had auditioned to be Shaggy in the 2002 live action film. The role was ultimately given to Matthew Lillard, who would later take over for Casey Kasem and work with Padalecki on the Scoobynatural crossover.
Thanks to Scooby Dooby Doo for the video link! :)
~ WildwindVampire ~