Now that we are talking about Scooby-Doo anyway I just wanted to recommend Scooby-Doo on Zombie Island.
I know the general consensus on the internet apperently is that I should hate Scooby-Doo now that I'm a grown up, but hey I liked Scooby-Doo as a kid and I found the old Hanna-Barbera cartoons kinda charming.
But what I like about Zombie Island is that it is a slightly darker Scooby-Doo movie that actually features real monsters, it's not a spoiler since it is one of the main plot points of the movie, and it's pretty well animated for a straight to dvd movie. And it's also way better than a straight to dvd movie have any right to be. On top of that it was kind of the perfect Scooby-Doo movie for me, because I saw it when I was a young teenager so I was a little too old admit that I still enjoyed Scooby-Doo, but it was also slightly darker than the original tv-show so I thought it was pretty cool at the time. Man, now I want to buy the dvd.
Anyway if you like Scooby-Doo and would like to see a slightly darker version with real monsters I highly recommend Scooby-Doo on Zombie Island.
If you like the darker scooby doo, watch Mystery Incorporated. Actually serialized, pretty effin dark (multiple character deaths), and just amazingly written.