For those of us over 60..

Kate and Anna McGarrigle.  Started listening to them and their entourage in 1975.  Still listening regularly and have expanded to their children:  Rufus and Martha Wainwright and the terrific Lily Lanken.   Their music encompasses all stages of life to me.  63 tomorrow!    

The WHO 

The Doobie Brothers and the original Peter Green/Fleetwood Mac bring back fond, nostalgic memories as well as the odd flashback, Oops. Better put Pink Floyd and The Electric Prunes in there as well.

I'm not quite 60 but for me it's the ABB followed closely by Cream. I still own much of the vinyl I bought in the 1970's, The Allman Brothers Band, Idlewild South, and Fillmore East and Disraeli Gears. I own quite a bit of fusion and funk from the same period - Billy Cobham -Spectrum is an almost weekly play as is The Mahavishnu Orchestra - Birds of Fire or Between Nothingness and Eternity. Probably should mention Santana also, first LP for me was Santana III.
It's probably not a surprise that I am currently running stacked "Large" 1973 Advents as my mains (also owned since I got them in the '70's)

Judy Collins, Joan Baez, and Dylan (I'm 79). :-)