Jordan
Best: 1991
Favorite: 1993 - the best combination of GOAT-level athelticism and skill-reliant game. Younger Jordan was much more into simply overpowering and blowing defenders by, while older lost some level of excitement he always gave us on the court.
LeBron
Best: 2012
Favorite: 2014 - I prefer watching LeBron in more off-ball oriented role and this version was possibly the best shooting verison of James ever. He still had that massive frame that could overpower anyone but used more skills in his repertoire.
Kareem
Best: 1977
Favorite: 1972 - Kareem's combo of athleticism and scoring skillset was absolutely insane that season. You won't find anyone like this before or since. He was very active on both sides of the court and he was less relaint on skyhook, trying to play more physical. Arguably my favorite individual season ever to watch and I wish we had more performances available from that season.
Russell
Best: 1962
Favorite: I don't think there are enough footage to say it clearly, but I like watching 1966 Russell games, he had enough scoring repertoire left while still being in his physical prime and possibly at his peak in terms of reading games. I prefer watching pre-67 Russell because he was much more active on offensive end, older Russell was quite mediocre on that end.
Duncan
Best: 2003
Favorite: either 2002 or 2003, I like watching my favorite player at his best

That said, I have a soft spot for 2007 and 2013 versions.
Wilt
Best: 1967
Favorite: again, tough to say with footage available. I like watching 1965 version because of how he adjusted his game to widened lane. He was still absurdly athletic by then, while having complete skillset and passing skills. I think 1966 would be my favorite verison of Wilt to watch, but we have very little footage from that season.
Shaq
Best: 2000
Favorite: 1998 - not a big fan of Shaq, but I like him in a sweet spot between young crazy athleticism and savvyness of older version.
Magic
Best: 1987
Favorite: 1990 - probably my ultimate offensive player to watch, he had no weaknesses with developed three point shot and I love how he became more post oriented after Jabbar retirement. Weak defense, but who cares - it's the best offensive player ever in my opinion.
Bird
Best: 1986
Favorite: 1988 - I don't know why, I like short haired Larry and he developed all of his skills by then.
Hakeem
Best: 1993
Favorite: 1990 - Hakeem's defense and motor was absurd that year, possibly the most athletic defender ever. He had holes in his offensive game, but who cares? 1990 Hakeem could bang inside with giants and in next posssession he could shut down Micheal Jordan in isolation.
Kobe
Best: 2008
Favorite: 2008 - I like older, more controlled version of Kobe over young and exciting Bryant from the early 2000s. His off-ball game was so good to watcg during that time.