I agree it’s tough but it’s Season 6 for me. The Dominion War and occupation of DS9 are very well executed. They do leave less room for single standalone episodes, but it includes many of my favourites, such as:Tough call. It's definitely Deep Space Nine, one of the later seasons, but picking between 5, 6 and 7 is difficult.
Ultimately I think it has to be 6. Peak serialisation without the breakneck pace of the final season, and lots of great episodes - The Magnificent Ferengi, Favor The Bold / Sacrifice of Angels, and of course In The Pale Moonlight.
QFTThe first season of The Original Series is my standout favorite, with the second season following as a very close second.
The first season of The Original Series is my standout favorite, with the second season following as a very close second.