Tough question to answer, Can one actually find episodes from 1974. My first was the 4th Doctor Who - Tom Baker 8 June 1974 – 21 March 1981. I couldn't watch the next few who I thought sucked. (Many people like the first Doctor Who they watch)
Many years later I picked it back up (my son liked the show) was the Doctor then, whom I liked, but he only lasted a season. He was followed by David Tennant who I had to grow to like, lasted almost 5 years. Then again the next Doctor Matt Smith, I wasn't a huge fan of.
Hoe many times can the Doctor kill off he nemesis decade after decade.
Pick up anywhere in the 2000's and you should be OK
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the spinoff Captain Jack Harkness was OK until they went over the top IMO with the homosexual activities weekly.