This is the original series, it introduced the original gang of Fred, Velma, Shaggy, Daphne, and of course, Scoobs. Every episode had ghosts or monsters, involved in some sort of mystery to solve. Of course, at the end of every show, the monster\ghost turned out to be fake, thanks to the gang. Makes you wonder how they always seemed to find places where people were pretending to be supernatural beings to pull of a scam...
Very similar to the first series, with the whole gang (minus Scrappy), with the same ghost\monster = fake, mystery type theme, just had a different name, basically.
Boo..Scrappy, he ruined the show! Anyways, enough of my personal opinion (mail me if you agree, or disagree about Scrappy being annoying). This series had only Scooby, Scrappy and Shaggy. The rest of the gang apparently went off, and took the Mystery Machine with them. Not so much a mystery show, just the adventures of the 3 day to day. If there were any monsters\ghosts in this series, they were real.
Similar to the above cartoon, except that they brought back Daphne (perhaps to get more young girl viewers), and it was located in different exotic locations every week (ie. Desert...mummies...coin, coin...). The main thing was, that the Mystery Machine was back! :)
I guess that they wanted to change the name of the show, as this series wasn't much different than the Scooby and Scrappy cartoons. Oh, and Fred would drop in and join the gang from time to time in this cartoon for some reason or another.
Shaggy, Scooby, Scrappy and Daphne were this time teamed up with Vincent Van Ghoul (voiced by the late, Vincent Price), and Flim Flam. Scooby releases 13 ghosts from an evil chest (you know, the kind that are always just lying around the house) and only the gang can put them back in it. A different ghost is featured every episode. Now, this series gives Shaggy and Daphne new looks. Shaggy gets new threads (other than his green shirt and brown pants look), as does Daphne, who also gets a new hairdo.
The name says it all. At the time, making old cartoon\kids show characters babies\youngens was popular (ie. Muppet Babies), so Scooby Doo got the treatment too. More comedy from all the characters now, and drawn more silly (the characters do wild looks, ie. eyes out of head, when ghosts appear). Daphne is more rich in this episode, Velma is on a skateboard, Scooby's dog house was huge and incredible (from the inside), and Freddie blamed everything on Red Herring. Oh yeah, and Shaggy was...well, Shaggy.
Featured stars helping out the gang, like the Harlem Globetrotters, the Three Stooges, Batman & Robin, Sonny & Cher, and Davey Jones. It had the actual voices of the stars. Quite an interesting concept, the gang sure was lucky to meet all those stars. They even got to throw ice all over the Globetrotters to help them win a game when they were tired.