The Simpsons. Full orchestra. Composed by Danny Elfman. Manic, obnoxious, bold, yet urgent and wistful at the same time. Captures the tone of the series (at least during the first couple of seasons) perfectly.
Six Feet Under. Haunting, simple melody. Bizarre Indonesian texture. Lots of creative mixing. Classic Thomas Newman of “American Beauty” fame.
the theme, composed by Angelo Badalamenti, lyrics by David Lynch, vocals by Julee Cruise for TWIN PEAKS
Mean Guy, glad you finally said something. I do love the Six Feet Under theme. I also find The Family Guy theme to be very catchy. I love the trombones (maybe synthesized?) on the upbeats (It seems today bop that all you see bop…).
Oh, I was also trying to think of old shows, and The Andy Griffith Show show came to mind. So fun to whistle with the hubby doing harmony 
Come on. It has to be:
The Prisoner
either that, or Gilligan’s Island.
The Alfred Hitchcock TV show theme.
Fat Albert.
BTW, Lizard, the ‘Buffy’ theme was done by ‘Nerf Herder’, IIRC.
It’s Schuberts piano sonata D959 in A, 4th mvmt.
Here is a midi
I’ll have to throw in another vote for MacGyver.
And I’ll cast the first vote for the theme to Sports Night.
I’m also particularly fond of the theme for the end credits of Dark Angel.
Performed by Isaac Hayes.
Ditto on Barney Miller
The Bob Newhart Show is one that deserves mentioning.
“Home to Emily”–composed, IIRC, by Lorenzo Music and his wife.
Maybe not the greatest, but certainly my favorite is the theme from HBO’s Real Sex series. The theme is actually a Perez Prado mambo-like song called “Patricia”, it fits the show perfectly.
Hawaii 5-0 overrated?
Surely you jest and, yes, I am calling you Shirley.
Personally, I like the 60 Minutes theme music. It has a nice steady beat.
James L. Brooks once referred to the Simpsons theme as “lemmings-marching-to-their-death music.” Although, of course, lemmings don’t really march to their death, I agree with him.
Mike Post’s stuff, which includes such memorable themes as:
The Rockford Files, CHiPs, Magnum PI, Hill Street Blues, The A-Team, LA Law (which perfectly captured the show the 80s, the show, and the feeling - those opening saxophones), Quantam Leap, the Law and Orders, NYPD Blue, etc.
Is generally great.
Of course, the iconic Twilight Zone theme wins hands down.
Some late comers to the party:
Sealab 2021, by Calamine: “If you’re looking for me / You’d better check under the sea”
Harvy Birdman: Attorney at Law: “Whooooo is the man in the suit? Whooo is the cat with the wiiiiings? Harvey attorney / Habeas Corpus / Marvy Attorney!” (Legend has it that the show’s creators wrote and recorded the theme song before they had a show. Their entire pitch to Mike Lazzo [VP of programming at Cartoon Network and the driving force behind Adult Swim] consisted of “OK, here’'s the idea. Harvy Birdman: Attorney at Law” and then they played the song. Lazzo immediately said “You’re in.” The demo they recorded is still used as the theme song today.)
And my personal favorite:
Cowboy Bebop: “Tank!” by the Seatbelts.
And of course I left out the best line in the Harvy Birdman song:
“Do you really want to feel him?”
My favorites are instrumentals:
1- Twin Peaks
2- Perry Mason
3- Andy Griffith
4- Diagnosis Murder
From the OP:
Babylon 5 had consistently rich, complex orchestral themes, changing each season to match the overall theme of that year.
Andy Griffith, and the Beverly Hillbillies
“Hills, that is”