I’m partial to 80s tv intros.
Ein Fall für Zwei
A hokey German detective show that’s still going strong. As the show progressed and the main character got older, the less stunts he made in the intro.
Knight Rider
That car is so cool.
The A-team
I love you Mad Murdock .
Macgyver
The title comes out from an explosion, this is the coolest thing ever!
Hustle
Wow, this would be a 99.9999% on match.com if you had also said "Welcome Back Kotter.
Oh well, your loss.
SSG Schwartz
Mission Hill. It’s an instrumental version of a Cake song.
Saving Grace
Pee-Wee’s Playhouse
Magnum, P.I.
It Takes a Thief. Terrific tune by Dave Grusin, and I always loved the pause for “Let me get this straight … you want me to steal?”
Especially the first season (I think they dropped it later) where you hear snippets of other stations as they’re moving along the dial.
“They’re genuine plastic, so don’t settle for cheap imitations!”
“And the senator, while insisting he was not drunk, could not explain his nudity.” 
Predictable for me to say: Doctor Who. For the same reason as The X-Files, which someone mentioned above: it set just the right tone for the show. Plus the original recording was electronically realized in the days before synthesizers - all test-tones from electronic equipment and tape segments of guitar strings, cut together and looped and cut together and looped…
Oo-wee-ooooooooooo…
Two of my favorites.
The NBC Mystery Movie, the original Columbo, McCloud, McMillian & Wife etc.
Gerry Anderson’s UFO
Not that I’m arguing with your sentiment, but surely you’ll agree that it’s not **possible **to have enough Bailey. After all, if such a quantity existed, then there would also be a quantity that was too much Bailey, and that’s just silly.
Hawaii-Five-0: great theme tune, classy camera work and stunningly beautiful girl.
Certainly **Mission Impossible **is a runner-up for the theme tune alone…
Great title sequence, sans credits: Lost
I LOVE THAT THEME!
Shame about my husband. 
Has anyone mentioned All In The Family?
What, no love for Miami Vice? It is like the Hawaii Five-0 theme updated for the Eighties.
The themes for Angel, Cowboy Bebop, and Doctor Who all do a great job of setting the tone for the show, are fun to listen to, and don’t overstay their welcomes. Those would be my picks.
Hogan’s Heroes.
Miami Vice. Remember how cool that show used to be?
FTR - both credits and opening songs/sequences are acceptable. I meant both in my OP - I’m just not as hip to the distinction as you Hollywood types are.
Submitted for your consideration (no, not Twilight Zone):
Miami Vice. No, not unique or very interesting (though good instrumental). BUT… the jiggling boob shot!! Shot DOWN HER CLEAVAGE!!! In the pre-internet porn days of the early 80’s, this was a seminal (snark!) shot.
Sua
Sprano’s opening theme it just sets the right mood.
Can’t top Airwolf though.
SCRUBS: Extremely short and simple, shows you all the main characters, what more could you want?
I also like the Big Bang Theory and Dexter for reasons already mentioned.
One I had not really thought of before until reading it earlier in the thread, but something I have to agree with. The muppets credits were excellent, totally put you in the mood.