Gotta be GI Joe. There's a lot of shows that could be in the #2 slot, but that cartoon more than any other really was my childhood favorite. Since I can still watch it without rolling my eyes (though not without some laughter at the silly, cheesy parts), it's gotta be top of the heap.

I'd guess Spider-Man and his amazing friends could almost bump GI Joe off the top spot then, but some of the writing is eye roll territory now. Same with Super Friends, though it wouldn't compete with Spidey.

If I picked a modern one, it would come down to exactly what you think of them in terms of being for kids. But it would be either Johnny Bravo or Powerpuff Girls (but only the original run). Johnny, it's dubious if it was really meant for kids or not, but I laugh at it more than PPG. But the girls hold a special place in my heart just because it was so well done as a kid's show that was watchable as an adult that didn't have kids. I'd watch PPG out of my own enjoyment, where I wouldn't with spongebob or most of the kid's cartoons of that era.