What were the most creatively fruitful times?
The chart above (click on it for a bigger version) shows the number of entries for each year from 1955 to 2008. There appears to be two big creative peaks - a massive peak from 1967 to 1979 (with a dip centred on 1976) and a smaller peak from 1987 to 1996. Major troughs were 1981 to 1985 and 2001 onwards.
1967-74: The flowering of the 60s - a creative explosion centred on 1969 which blossoms and matures over the next 5 years. I can't imagine we'll see anything like it MUSICALLY in the lifetime of anyone now living. There will be creative explosions, just not in music. My money is on the fusion of gaming / filmmaking / TV and other immersive / interactive technologies. With respect to those art forms we are in the equivalent of the 1950s - the big breakout is 5 to 10 years away.
1976: Wha' happen? A transitional moment. To oversimplify, the music forms that had their genesis from 1967 to 72 had run their course - the UK punk counterrevolution was gearing up.
1977-79: Ramones, Stranglers, Clash, Talking Heads, Bowie (again), Iggy, Television, Elvis Costelle, Pistols, The Jam all hitting their stride.
1981-85: The counterrevolution had been co-opted by the mainstream and pureed into new romanticism. Something weird happened to production values.
1987-96: Manchester, grunge, rap, hip hop - Jesus & Mary Chain, Sonic Youth, Mudhoney, Jane's Addiction, Stone Roses, Public Enemy, Soul II Soul, De La Soul, NWA, etc