I have a few, for me music died with Kurt Cobaine 5th Apr 94 , Bob Marley 11th May 81
Whitney 11th Feb 2012 and Amy Whinehouse 23rd July 2011 as you can see i have a varied music taste lol
I'm sure it was a phrase before Don McLean coined it in song.
For me, it was the forming of the "27 Club." Musicians dying at 27 -- all within a year -- Jim Morrison, Janis Joplin, Jimi Hendrix (Amy Winehouse and Kurt Cobain would be later members of it). Robert Johnson was the first in it.