the early 90's were fantastic for cartoons. Warner Brothers resurgence in animation was phenomenal and brought a slew of fantastic new content to the scene. Add to that the rise of the Cartoon Network when they started their own content in the mid to late 90's and the huge rise of quality Anime in the US, i would say the 90's were the best decade for cartoons period.
Dont get me wrong. I love the old old old stuff from the early 20th century. Lots of charm and fantastic characters in its own right, up through the 40's and 50's.
I was never all that into the Hanna Barbera stuff, though a lot was good stuff. Who doesnt like Scooby Doo?
80's cartoons were junk for the most part looking back. I saw a small sliver of Robotech when i was 4 and it hooked me instantly. I never knew what it was till years later.