List of albums that will still be popular 50 years from now...

“Disco Baby” by Van McCoy and the Soul City Symphony.

Fo’Shizzle.

I'll bet on:

Chuck Berry as the moving force in delivering a "race music" soundtrack for the counterculture of the 1960s and Elvis and The Beatles (very possibly Brian Wilson, too) as the moving forces in co-opting that back for mainstream Western culture and commerce.

The social context of rock n roll is important and my guess is that the r n r music that survives the longest will be that which played a pivotal cultural role, per the above.

Some of the Brill Building music (Carol King Tapestry, etc) may survive, too - but that's a different (not r n r) kettle of fish, IMO.

Czarivey, it's a long process, it takes time. But I am on my way, I gradually stop listening most of what I have been listening.
In 500 years it is possible that humans will change quite dramatically, perhaps becoming sort of enhanced humanoids or something else, and music as we know it will be irrelevant.
But in the near future Western and Middle Eastern classical music should survive.

Indian classical music too.

Inna,

Nearly 20 years ago, I stopped listening almost every popular title listed here (simply got bored and please DSOM, LZ and RS listeners don't get offended, but it's true) and listen to mostly what's strange, weird, unusual and sophisticated plus indeed classical music. I get far more joy from Michael Rabin than from Michael Jackson for sure!

I'm seller of music for VERY long period of time (since my early teens) and as once Scarface told, I "don't get high out of my own supply" and usually what I sell I can only listen for grading purposes.