"This is Jeopardy!" is up there for me. I actually like it in its current form better, because it seems that Johnny Gilbert puts even
more punch into those three words than back when J! still had the swooshy globe thing on their logo.
Also a +1 to Gene Wood's Feud intros, and let's add PYL to the pile too. (Straw poll: do you prefer "After high stakes" or "big bucks"?)
And not really a "spiel" per se, but I always got a giggle out of Bill Anderson and Sarah Purcell pantomiming the dooba-dobba-deeba-dooba-dop-doo-wops (okay, fine,
you transcribe that!) in the theme to
The Better Sex.
"Every answer to every question is right here before your eyes...and...now...you...see...it." Perfect match of graphics, intro language, and music.
What I didn't like about that intro was how they hacked up the music by cutting out a beat or two during the "Now!" (da da da da, da da da da) "You!" (da da da da, da da da da)… etc." part. It made the song sound a bit staggered and uneven to me. (Although I believe in earlier episodes, they didn't do this.)
"In a moment, a game that intrigued a nation. In a moment, the game strategy, knowledge, and fun. In a moment, TIC-TAC DOUGH!"
That one has always struck me as comically hyperbolic. Which, in a way, fits TTD'90 like a glove.