I agree about the cast, for sure - and Robbie Coltrane - he was fab as Hagrid. Can't imagine anyone else playing that role.
And Friends - another brilliant cast loaded with character and chemistry, along with excellent stories and acting.
One other - the Big Bang Theory. Man - absolutely incredible, start to finish.
I can see why this series left such an impression on you, as you were 5 when it was first out. I was - uh - a little older than that. Although I love magic and the occult (and have been known to practice witchcraft for a few decades), it didn't have the same appeal for me beyond the first couple of films.
But it's lovely that you've had this truly "magical" part of your childhood and growing up years. Precious memories!