It's the best and I will fight you on this.
Now of course I'm biased, I saw this at a young age and fell in love with it. But why? Why this movie above every other? I can't fully say. It has a great story, the gang meet a famous writer Ben Ravencroft who invites them to his hometown where apparently the ghost of his ancestor who was convicted of being a witch has returned. It has probably the best finale to any of the Scooby-Doo movies, the acting is great especially when you get a powerhouse like Tim Curry fully devoted to his role. Add good comedy, great animation, and the best and so far only recurring characters in the series history to return periodically. I refer of course to The Hex Girls, who I am even more biased towards because quite frankly I love them and the music they perform in the movie. But it goes deeper than that, this is a terrific fall movie, I mean like if you put it on in October it has that exquisite fall feeling to it all and perfect for Halloween. The nostalgia has skyrocketed, I watched this movie all the time, day, night, I adored it as a kid and the love has never died. The animation is crisp and fluid, the comedy actually does make me laugh at times, the characters are memorable, the music is fantastic, this just holds the title for best Scooby-Doo movie ever. This and my old tape of Scooby's Greatest Mysteries, and of course Mystery Incorporated are the crown jewels of this series for me. You wanna know why I persist to love this series even to this day? Watch those and the original show. And the best part? I share a birthday with Shaggy Rogers. Happy Birthday Casey.