For me, just off the top of my head:
Battlestar Galactica
House
Sherlock
M*A*S*H
Magnum P.I.
Justice League
Spectacular Spider-Man
Justified
Star Trek: The Next Generation
Star Trek: Deep Space Nine
Ghost In The Shell: Stand Alone Complex
Cowboy BeBop
The Tunnel
Hmmmm..... would agree with some of that.
Justified - started strong and just got better and better, probably the most satisfying finale ever. A truly great show.
Battlestar, MASH and Magnum PI, all have a few hit and miss episodes but were otherwise great - particularly MASH ! I've never seen the finale of Magnum sadly.
Sherlock, I feel like it peaked in season 2 although the wedding episode was great fun. Season 4, particularly the finale I found a bit too far fetched even for a Holmes story.
Justice League is great fun, although I've only seen seasons 1 and 2.
House....lost interest after season 2, enjoyed the finale though.
Never saw spectacular Spider Man.
Okay, as a big trek fan back in the day I have to say that IMO TNG did not hit it's stride until season 3 - which might just be the best season overall ( there are great standout episodes in other seasons but I feel like season 3 took the show to a whole new level). Also later seasons had more than a few filler episodes. The finale was just magic, another one for the GOAT list.
DS9 again for me it didn't really hit stride until things really heated up with the Dominion War. The show started off as a sci fi version of Bonanza and turned into an extended version of Winds of War. Another great finale though.
Haven't seen the others
I would add to the list....
Fringe ( it loses some steam in the first half of season 4 but then recovers).
Person of Interest - I have some issues with the final season but otherwise it was great.
Firefly......great show right from season 1 to, oh never mind.