Spider-Man
Wonder Woman
Barney Miller
Just another vote for “Walking on Air,” a.k.a. the Greatest American Hero theme. The extended version is definitely worth hunting down for a listen.
I always liked the theme to Rockford Files, and Simon & Simon had a catchy little guitar riff.
Guiltiest pleasure: “Just two good ol’ boys…”
I nominate the Hill Street Blues theme song. Never even watched the show, but love that music. I took piano lessons for four years with the ultimate goal of being to be able to play that piece–which I eventually did! 
I also second (third, whatever) Greatest American Hero.
Why, the X-Files of course!
And how can we forget the theme to Six Feet Under?
I agree with the already mentioned Greatest American Hero and Cheers. Two more I’ve always liked are The Courtship of Eddie’s Father and Welcome Back Kotter. I’d throw in the Simpson’s version of All In The Family (“for no reason here’s Apu”), but I guess that doesn’t really count.
I always liked the “Happy Days” theme… not Rock around the Clock, but the actual song “Happy Days.” I also liked the “Family Ties” song, as well as “Green Acres” and “Petticoat Junction” because they’re just do darn catchy and funny.
**Car 54 Where Are You? ** and
MST3K
Mannix-great, swingin’ tune
For the best “describe the main plot point” theme song, I nominate “The Nanny”. It’s kicky, cute, and tells the basic story of the show quite well. To bad the show wasn’t better.
The “Angel” theme is just gorgeous. I remember the theme to “Days and Nights of Molly Dodd” also used strings, but in more of a jazz setting.
My favorie though, is “Harlem Nocturne” which, while a standard,
was used as the theme to “Mike Hammer.”
Wrong, wrong, wrong. The best theme song ever is Space: 1999. Overwrought orchestra, to disco, and back again. A thing of beauty.
It’s neck-and-neck with Lost in Space, which would have won except both of that show’s themes are excellent and end up splitting the vote.
And you have to give credit to UFO, a precursor to Space: 1999, too.
I like the “Cleveland Rocks” intro to the Drew Carey Show. I’ve always liked The Munsters song too, preferably from the episodes where Herman crashes through the front door.
My pals Laverne and Shirley.
Peter Gunn Theme
Got Yourself a Gun theme for The Sopranos
I kinda partial to the Jeopardy! theme music also.
“Mission: Impossible”
“Hawaii Five-O”
“The Rockford Files”
As for MST3K, the end theme is one of the greatest instrumental TV themes EVER. MSTies were forced to unite and petition Comedy Central to get the Penn Gillette voiceovers removed because it interefered with the enjoyment of said theme song.
The Rockford Files
Peter Gunn
The Bob Newhart Show
Barney Miller
Scrubs
The John Larroquette Show (first version)
The Prisoner
Jonny Quest
The Tonight Show (Johnny Carson era)
And the all-time best TV show them is: Cowboy Beebop!
Hawaii Five-0
A bunch of good nominations here, I like Hawaii 5-0 and Peter Gunn too.
I’ll nominate Miami Vice. I think it was Jan Hammer’s band? The instrumentals…the percussion section was awesome, that song is still one of my all time favs.
Rocko’s Modern Life, the first version.
“Who can turn the world on with her smile?”
And while I can’t recall if it had a theme song per se, the music for “Cosmos” is great, esp. Vangelis’s Heaven and Hell.
And who can forget the “Larry Sanders Show” theme song?