Honestly very few shows I've watched and was a fan of were able to end before they started jumping the shark and coming off the rails. Some had a single rocky season but a strong finale like TNG. BSG could fall into this category too since its final season was all over the map and wandered aimlessly intentionally dragging stuff out then half-assing the mythology but it did manage to pull out a great finale. Some not only had a crappy final season but several mediocre years and a bad series finale to boot i.e. The X-Files, Roseanne, Melrose Place 1.0
DS9 had a bit of a rocky start to its final year but halfway through and it took off and never looked back. To this day the Final Chapter is my favorite sendoff. DS9 is how you want to end--at a point where you feel like there is another season or more of stuff left to do. It was epic storytelling at its finest with those great scenes with all those wonderful recurring characters, epic stakes, the way Bajor and Cardassia came full circle, nice character arcs for the cast, emotional good-byes, writers drawing on a myriad of disparate threads and pulling them together.
I thought LOST would actually unseat it. Granted there are 3 episodes left but judging just the 15 episodes so far--it doesn't look like that is going to happen. I think I spoke too soon a few months ago in the fall when I was talking like LOST was going to knock my socks off with its last year. It certainly seemed like that was the trajectory it was on with the most consistent stretch of episodes ever spanning several years and strong writing but this season was a little underwhelming. It had lost that narrative purpose, focus and sense of urgency it had from seasons 3-5. The new characters they introduced just were flat and not like the calibre in those other seasons. The pace was slow, the stalling tactics were back, the season has been pretty much characterized by a lot of mechanical logistics and plot movement consistin of back and forth movement on the island.
The way it stands now LOST is better than a great deal of other series' final seasons but not up to the high standards the show had established and I was expecting.
