For me it goes like this:
Season 1 : Beryl and Kunzite takimg Mamoru away. These screams were amazing and the whole act 9 was great
Season 2 : Pluto's death and Black Lady reaction. It still gives me chills.
Season 3 : Hotaru becomes Mistress 9 and takes Chibi Usa's Silver Crystal. Still gives me chills.
Overall if you binge-watch Crystal, it really makes a greater impact. Dead Busters is the best story-wise, but I have never been a fan of the artstyle. Black Moon was, artstyle-wise the best in my opinion, so I go with it, even though it is the weakest arc when it comes ti story.
Eternal, so far though, from all the leaks we saw, while not perfect, will still have a lot of great scenes and adapting my favourite Dream Arc, so I am fairly certain the poll will look different once it is out.