First of all, I came from a non English speaking country.
So, this show is the few thing that make my English learning really fun. With the sing a long, spelling, et cetera I just can wait for the next letter or number to be introduce.
My personal favorite will be Bert and Ernie, because despite all their differences, they truly are the best of friend.
And then there is Kermit and Ms Piggy, the true love of all time. As I grown up, I still love this show, I watched it with my nieces and nephew now. Learning is always fun with Big Bird, Elmo and friends.