Along with those mentioned by @tostadosunidos, I would add The Flying Burrito Bothers’ Gilded Palace Of Sin, Louisiana Man by Doug Kershaw, A Salty Dog by Procol Harum, Lost In The Ozone by Commander Cody & His Lost Planet Airmen, Where’s The Money by Dan Hicks & His Hot Licks, Sneakers by The Flamin’ Groovies, Loosen Up Naturally, The Sons, and Follow Your Heart by The Sons Of Champlin, Arthur, Lola, and Muswell Hillbillies by The Kinks, Song Cycle by Van Dyke Parks, 12 Songs and Sail Away by Randy Newman, Sunflower and Surf’s Up by The Beach Boys, Seatrain (2nd album) by Seatrain, Crazy Horse by Crazy Horse, Moondance by Van Morrison, but most importantly The Band (aka the brown album) by The Band, along with it’s follow-ups Stage Fright and Cahoots. Also George Jones, Tammy Wynette (I’m still in love with her), Loretta Lynn, Buck Owens, Johnny Cash, and Merle Haggard.
Then there were collections of the earlier artists and groups I was discovering in my explorations into Rock ’n’ Roll’s roots: Hank Williams, Lefty Frizzell (discovered via The Band including his "Long Black Veil" on their Music From Big Pink album), Little Richard, Louis Jordan, Big Joe Turner, Jerry Lee Lewis, Buddy Holly, Elvis’ Sun Sessions, Carl Perkins, The Everly Brothers, The Carter Family, The Coasters, The Clovers, The Drifters, all the girl groups of the late-50’s/early-60’s, and a whole lot more. THAT was my real education ;-) .
In Classical, it started with Stravinsky, Holst, Wagner, Beethoven, Mozart, working my way back to The Master, J.S. Bach.