If the theme is by Mike Post, chances are I love it. Favourites:
Hill Street Blues
NYPD Blue
The Rockford files
Magnum PI
LA Law
The Prisoner got a mention earlier for it’s terrific theme tune and I agree and observe that its spiritual foreunner, Danger Manis also brilliant.
I also really loved the credits to The Waltons with all the sepia photographs and that melancholy Jerry Goldsmith penned tune -it was the only bit of the show I really loved, in fact. Taxi and Grandstand (long running UK Sports Programme) also had fantastic theme tunes.
For sheer earworm quality, I think the 80’s cartoon “Around the world with Willy Fog” is hard to beat. As a pleasing bonus, Fog sounds like James Mason.
However, if I’m including both the music and the visual appeal of the credits, then I second the vote for Police Squad.