Most certainly the 1960s. I mean, that was literally the decade of the golden age. Sure the stories may be more childish than stuff that came later, but they were also joyful and had such energy that no one has been able to retake it. As much as any character from that era (save perhaps cinema's James Bond), Spidey is a product of that time and many of his great stories were from that time. Almost all his A-list villains come from that era and it was the time of Gwen or MJ, Harry and Peter in college, Captain Stacy, MJ's retro flip, MJ's shorthand not being retro, Flash going to Vietnam, authority figures vs. the smartass and skeptical youth (Doc Ock, Vulture, Norman Osborn, even the Lizard a little bit), Lee/Ditko, Lee/Romita(!), etc.
There is a reason why most animated shows and the Raimi movies pulled heavily form those comics. They were Spidey in his prime. The golden era. Something Marvel tried (and failed) to recreate with BND, so now they're aiming for later periods.
After that, I'd agree the 1980s were had a lot of great stories. They took characters created in the '60s and '70s (MJ, Black Cat, Hobgoblin, Harry Osborn, The Kingpin, Flash Thompson, etc.) and gave them a lot more depth. They became more their own full fledged characters instead of ancillaries of Peter Parker. MJ became Peter's confidant, and eventually his wife, Peter left school, Peter had some rather, shall we say more "adult" or mature relationships (such as his growing weariness of Harry, eventually marriage, his....odd relationship with Betty Brant/Ned's wife, etc.) plus it had the gang wars, the mystery of the Hobgoblin, the Black Suit, the Black Cat Affair(s), Kraven's Last Hunt and Venom.
Pretty good era that maybe the new Spidey film franchise can pull from. The '90s started well but ended badly (IMO). Not because of the Clone Saga, but everything a year or two out from that that was meant to "clean it up" (bringing Aunt May back from the dead, having Peter forget he had a daughter, "killing" off MJ, etc.). Kind of like how I thought the last decade started strong with Jenkins's run, the early JMS/JRjr run, Mark Millar's run, etc....Then it all came to a screeching halt with Sins Past and was downhill from there out for at least five years with The Other, Civil War, Back In Black, One More Day and Brand New Day.
Anyway, the '60s and then the '80s get my votes.