I remember Osama Tezuka's ASTRO BOY as being my mostest favorite series when I was about 4.
By age 5, my tastes were more refined and MARINE BOY with his oxygen gum was my favorite, I remember the first time I saw those brilliant colors while visiting the home of a friend whose parents could afford a color TV!
By 1969, however, PRINCE PLANET came into rotation on a new UHF channel and I began wearing a pendant all the time. In fact, I still have it in the drawer directly in front of me!
But the best was probably SPEED RACER by 1970, colorful and creative with lots of action and likable characters. Many, many years later, I spoke on the phone with Corinne Orr who was not only the voice of both Speed's girlfriend AND his little brother but also the above-mentioned Marine Boy!
Honorable mention must be given to this guy, ALAKAZAM THE GREAT, a feature-length Japanese anime based on the Monkey King legend, dubbed into English with celebrity voices like Frankie Avalon and Jonathan Winters and frequently shown on television throughout my childhood.