For me, the Infinity Arc of Sailor Moon is my favourite because of Michiru and Haruka.
Back at the turn of the century when I was learning Japanese via a terrible translation and an anime dubbed to death where Michiru and Haruka were 'cousins' because you just could not have a gay relationship. Ever. This was a big thing and I remember ordering the 'uncut' DVDs, produced by Pioneer and Geneon, directly from the States just for the art and the suggestive cover that said there was no way in hell these two were related biologically. Michiru was always my favourite of the pair, beautiful, feminine, artistic but I also liked that Haruka made 'boy stuff' cooler for girls. It was okay to like cars and bikes, to kick arse even if you happened to be a rather butch female.
This was also about the same time I realised I really preferred women to men and so having such role models, albeit watered down for public consumption, was a great experience.
Now we're returning, with thirteen episodes of Sailor Moon Crystal's third season, starting next week and I'm excited. I love the ending theme, sung by the voice actors for the pair, and the new opening theme is growing on me too (including a cameo from NQS, or at least Princess Serenity wearing a very NQS crown). The animation is so much better, as demonstrated in the video above.
I can't wait, it's going to be a great and, hopefully, authentic return to my favourite series.