When I was a kid...
1. X-Men
2. Animaniacs
3. C.O.P.S.
4. Transformers
5. Darkwing Duck
6. Batman: The Animated Series
7. Tiny Toons
8. The Simpsons
9. Gargoyles
10. Ren & Stimpy
Honourable mentions: Teenaget Mutant Ninja Turtles, Duck Tales, Tail Spin, Denver the Last Dinosaur, Ewoks, Gummi Bears, Dino Saucers, Dino Riders, The Real Ghostbusters, Chip n' Dale Rescue Rangers, Aladdin
As an adult looking back and also with what I'm watching these days...
1. X-Men
2. Animaniacs
3. Tiny Toons
4. Futurama
5. American Dad
6. Family Guy
7. South Park
8. The Simpsons
9. Batman: The Animated Series
10. Gargoyles
I don't watch too many cartoons these days. Mostly anime.
Anime that get honourable mentions for being seen as "a cartoon" to me as I watched them amongst other cartoons while I was growing up, ie, before I really knew what anime was...
1. Samurai Pizza Cats
2. Pokémon
3. Dragonball Z
The first two would almost certainly get into my top ten cartoon list, both old and probably new.