The 70s and 80s
I disagree with one reply that said the depth of the tour is deeper now. The 70s and 80s were every bit as deep. In the 70s of course you had Borg, McEnroe, Connors, but you also had Arthur Ashe, Stan Smith, Vitas Gerulaitis, Ille Nastase, Guillermo Vilas, and the end of the Australian dynasties with Rosewall, Newcombe, and Laver! Not to mention players like Brian Teacher, the Gullicksons, Jan Kodes, Taner, Dent, et al. It was a great era!
Another point of diagreement I have is that not everyone hated John McEnroe. John, Bjorn Borg and Vitas Gerulaitis were the best of friends. John and Jimmy got a long off the court (but from all accounts Connors is a hard guy to get close to). Lendl always seemed like the black sheep of the tour, but that can be attributed partially to his competitive philosophy that, similar to Connors, never got close to anyone. Lendl also wasn't a media darling like Connors or Borg, and his accent and acceptance of eastern Europeans at that time was difficul for him to become popular.