EDITOR'S OPINIONFirst of all, let me just say that Scrappy-Doo is one of my least favorite characters in this franchise. I realize he was needed in order to replace the other gang members but in my opinion they should have never written the other three out of some of those series. I would much rather watch and listen to Fred, Daphne and Velma than ever have to hear Scrappy say 'PUPPY POWER!!' again.
That being said the choice for me as my favorite Scrappy voice is easy. In this case the old phrase holds true, the original is the best. I think Lennie Weinrib nailed this character and he made the character a little less annoying than his successors did. Don Messick is a legend and Scott Innes is a great voice imitator but Weinrib gets my vote.
1st: Weinrib, 2nd: Messick, 3rd: Innes