We didn't have a TV for what seemed a long time when I was young - I once referred to Jackanory as a person ("Who is he?"), but I did see Andy Pandy somewhere (I did not like it: I must have been too old: same with The Woodentops, though that did have a certain charm; and the fascination of what was over the fence).
So, for me children's TV really came into its own with the Trumpson and Small Films shorts, which I still enjoy seeing. Later, I enjoyed Chorlton and the Wheelies (I used to go to my girlfriend's from work to see it during the dinner break), and again later, Pipkins (which I used to watch when living in a squat in Shepherd's Bush.
Other things I've found later:
The Enchanted Castle, which I saw when it was on first, or some of it anyway, in about 1978. It was the one with the statues in the garden coming alive at night. It used to be on Youtube (yes, I did get a copy of it) but this clip is all that remains: