The greatest year in pop music history...

Except music that's unpopular.
Unpopular, as in music not a single person liked is excluded. So yes, for example kyrgisian dodecaphony with finnish lyrics doesn't fit the bill
 
1967 was pretty pretty good.
Younger Than Yesterday - The Byrds
Mellow Yellow - Donovan
The Doors - The Doors
Sgt. Pepper's Lonely Hearts Club Band - The Beatles
Buffalo Springfield - Buffalo Springfield
The Grateful Dead - The Grateful Dead
The Velvet Underground and Nico - The Velvet Underground
Bee Gees 1st - The Bee Gees
Are You Experienced? - The Jimi Hendrix Experience
Little Games - The Yardbirds
Wild Honey - The Beach Boys
Magical Mystery Tour - The Beatles
Pisces, Aquarius, Capricorn, & Jones, Ltd. - The Monkees
Their Satanic Majesties Request - Rolling Stones
The Piper at the Gates of Dawn - Pink Floyd
 
1967 was pretty pretty good.
Younger Than Yesterday - The Byrds
Mellow Yellow - Donovan
The Doors - The Doors
Sgt. Pepper's Lonely Hearts Club Band - The Beatles
Buffalo Springfield - Buffalo Springfield
The Grateful Dead - The Grateful Dead
The Velvet Underground and Nico - The Velvet Underground
Bee Gees 1st - The Bee Gees
Are You Experienced? - The Jimi Hendrix Experience
Little Games - The Yardbirds
Wild Honey - The Beach Boys
Magical Mystery Tour - The Beatles
Pisces, Aquarius, Capricorn, & Jones, Ltd. - The Monkees
Their Satanic Majesties Request - Rolling Stones
The Piper at the Gates of Dawn - Pink Floyd



Never mind the Bollocks, released in 1977, was more influental than all the above. Well, Velevet Underground was great, I guess.
 
Never mind the Bollocks, released in 1977, was more influental than all the above. Well, Velevet Underground was great, I guess.
The Stooges were as much of an influence of that kind of music as the Sex Pistols. Raw Power released in 1973 inspired many great artists but in terms of fashion and overall attitude the Sex Pistols and Never mind.... is more influential.

The Velvet Underground and Nico is often on the top on lists about the most influential albums.

But your question was about the best year in music, so my instinct tells me that it has something to do with a year, the best albums/songs were released.
If your asking about a year with the most influential on modern music I would suggest the year they invented the electric guitar.