While there isn't a formal "favorite season" concept, I feel that most of Bob Ross art points to certain seasons or episodes as being particularly popular or helpful for beginners. I personally love Season 8, what about you?
I like Series 1; it's just no-nonsense, rugged landscape paintings, which is what I like most!
dracula thats a good series too, he talked more about what he was doing, more first time painter friendly.