The first thing that came to mind when I saw this thread was the $10,000 Dash from The Moneymaze. However, to be honest, I can't definitely put it above the Winners Circle.
Other choices: the Mystery Tune from $100,000 Name That Tune in its first two seasons. and the bonus round from All-Star Baffle (a contestant from the studio audience had to get nine words in 30 seconds from three-letter clues).
Honorable mention - not for how exciting it was, but for going against the flow; on the Bill Cosby version of You Bet Your Life, you had to pick one of three envelopes to see whether or not you were playing for $10,000, and you had to answer one final question - but in this case, the question came first, so if you got it wrong, you didn't have to suffer the humiliation of finding out you would have been playing for the $10,000. (Imagine if somebody was to even suggest doing something like that with the Wheel of Fortune bonus round.)
-- Don