For movies, I think that the 70s and 80s were the best for them, because of the amount of creativity that went into them. Movies from the 90s on are reboots of reboots and are generally stale.
For music, I think music took off in the 60s with rock, and continued on with the various metals from the 70s til now. We just don't ever hear any of it (especially the new stuff) because that's not what the record companies want us to hear, so it gets suppressed.
For tv, I would also say 70s and 80s, though some 90s stuff is good. I generally don't like tv all that much, so I can't say with any certainty. But no one will ever try a show like All in the Family again. The Simpsons and South Park will be the closest we ever get to having the social commentary that All in the Family was known for.