Major game-show aficianado here...
For some reason I liked the quiz-type shows, even though as a kid I couldn't answer many of the questions. Twenty-One and The $64,000 Question were before my time, but I well remember the original version of Jeopardy!. There was another show on about the same time with the unwieldy name of The Who, What or Where Game, which was even better. And in the early '70s there was one called Split Second which had great strategy and, true to its name, was incredibly fast. (And the odd bit about that was that it was produced by Stefan Hatos and Monty Hall... and it was about as different from Let's Make a Deal as anything could ever be.) I agree that the original version of Password was the best; the game play was more straightforward, and I still like catching the reruns on GSN with the cool early-'60s set and the jazzy theme. Allen Ludden died much too young. Sigh.
Concentration was a favorite too, as was the original version of The Match Game (although I admit that the '70s revival was better). I remember watching the original version of TPIR but I don't recall much about it... I keep getting it confused in my mind with Supermarket Sweep, the original version of which was on about the same time. And, the only reason I was ever able to sit still through Lawrence Welk on Sunday night was because, if I sat still through it, I was allowed to stay up and watch To Tell The Truth next ("Mom, two of those men are *lying*! And they let them!")
Nowdays, it seems like the ones I like the most don't have very long runs. I liked 1 Versus 100 and Identity. I really liked GSN's revival of I've Got a Secret. It was great because they updated the show and they had fun with it, but they didn't mock the concept.