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

I've been teaching pop music on guitar (and other instruments) for over thirty years and I'm amazed that "our" music survived the generation flip.  It boggles my mind that I'm still showing kids how to play Beatles, Cream, Hendrix, etc.  The music is 50 years old.  That said, I had two young sisters in the last ten years who only wanted to play swing and western swing--nothing post-World War II.  They've finally come around to more be-bop flavored stuff.  I was born in the 50's but I love a lot of the jazz and solo delta blues from the 20's, 30's and 40's.  A lot of the best stuff will survive, especially the best known (such as Elvis, the Beatles, Led Zep, Michael Jackson, Nirvana).   I'm not qualified to comment on hip-hop or rap as they are outside of my realm of familiarity/understanding.

Pt. II--If the best known stuff is still heard and appreciated then the question becomes:  which of the lesser stuff survives--the Pixies?  Screaming Jay Hawkins?  Blues Magoos?  Jan and Dean?   We can't know.  You have piqued my curiosity about something that I can never know the answer to (unless I live to be 114).

@ghosthouse : I was thrilled to discover Porcupine Tree because I just "knew" there Must be something similar to PF, like in the 90-ies (only then) I finally "discovered" Electronic Music of TD and KS, by listening to Pink Floyd..  First I just imagined the music, then, through Kitaro I found it! In another 50 years, its a good question how those kids are going to discover Sergeant or Gaucho? Definitely Not by listening to Top 30 ;-)

I think there will be many many artists whose work will still be regarded 50 years from now. 
Achtung Baby from U2 is a classic!
AcDc, Iron Maiden and Metallica will always be heard. 
Different styles like Morcheeba, Zero7, Thievery Corporation... will be around for many years. 
Music is something that is constantly being rediscovered by younger generations. If there is some quality in it, it will stick around. 
I'm 40 years old, I have some musical knowledge, played some instruments a long time ago and have been discovering new artists and styles since I was a child. From Nirvana to Vivaldi, Beethoven to Megadeth, I've always loved all kinds of music and I love to discover new artists everyday- some of them passed away more than 50 years ago...
Next week I'm going to watch a classical ballet: The Swan Lake. And in January I'm going to the Metallica concert in Hong Kong. And only a few years ago, at the age of 35, I started to listen to the Beatles. And I found them sooo good that I'm buying every record from them. 
Just to say that 50 years from now there will be people listening to what is being made today. 

Tostadosunidos,
Some hip-hop and rap is backed up with great instrumental and funky work!
Speaking of rap 

Bestie Boys -- "Lisence to Ill" has VERY good chance to live 50 years more from now as it's almost lived already half-the term so as albums down bellow:
Public Enemy -- "...Nation of Million..."
Run DMC -- "Raising Hell"