In no particular order:
Four Way Street - Crosby, Stills, Nash and Young
At Fillmore East - The Allman Brothers
Sgt. Pepper's Lonly Hearts Club Band - The Beatles
Born To Run - Bruce Springsteen
The Doors - The Doors
The Wild The Innocent and the E Street Shuffle-Bruce Springstein
Blind Faith-I saw them with Kelly McKee
Days of Future Passed-The Moody Blues
Funk-James Gang
Dragonfly-Jefferson Starship
Joni Mitchell - Blue (also like her More recent jazz...)
Jim Croce - Photographs & Memories (or just about anything...)
Fleetwood Mac - The Dance (ditto)
Lucinda Willliiams -- This Sweet Old World
Jose Felliciano - Feliciao!
Anything by Mickey Newberry is worth it. So that's #1. He never got famous except in songwriting circles, but his songs have been covered by lots of people and his singing technique is alternately soaring, raspy and melodious, sometimes in the same song.
#2 is Court and Spark by Joni Mitchell - wore out the album in college nad play it now on CD.
#3 is Jackson Browne's The Pretender - later in the 70s, but he's also got a way with word and ideas.
#4 is Leonard Cohen, another gifted songwriter who caught my ear when 'Suzanne' came out in the fall of 1967 and I bought an album shortly thereafter.
#5 Hoyt Axton - voice like melted butter, he was a wordsmith who seemed to write mostly country songs. He was versatile, though, as he wrote Jeremiah Was a Bullfrog, sung by Three Dog Night. It was the most popular song of 1971.
#6 - anything by Neil Yong - can't leave out ol' Neil, no matter what Lynrd Skynrd had to say about him.
Mike, and Jim n Gary,
None of us can stop at just 5 Albums. Truth, I have worn out 3 Blind Faith Albums. I already want to swap everyone. When the singer Bonnie Raitt ??? fell off the stage and broke her arm at the Blind Faith Concert in Phx., she fell on me n kelly. It might have been another woman singer.
Who Knows Where the Time Goes -- Judy Collins This has some Leonard Cohen pieces in it. This album is about 'The West' to me.
The Best of Steely Dan, Expanded Edition -- Steely Dan Includes 'FM' and some Fagen-only songs at the end.
The Nightfly -- Donald Fagen Won't you please turn your radio down?
The Best of Emerson, Lake, and Palmer -- ELP Man o' man 'o man what a great album.
The Best of Manhatten Transfer -- MT What more can I say? These guys can sing.
Passage -- The Carpenters (okay, yeah, this is six) Has Leon Russell, Tom Scott, and Cubby from the Mickey Mouse Club in there.
And in my MP3 player, there's 'A Salty Dog' by Procul Harem, 'Ruby' by Kenny Rogers, 'It's So Hard To Say' by Dan Fogelberg, 'Motherless Child' by Sweetwater, 'Hot Summer Day' by It's a Beautiful Day, and (drumroll) 'You're the One That I Want' from Grease. When I grow up, I want to be a bass guitar.
One more: For me, the quintessential tune for the late sixties is 'You Showed Me' by the Turtles. I never tire hearing it. Strangely enough, it was written by Roger McGuinn of the Byrds.
A runner up to this is a song I never hear anymore, 'Morning Girl' by the Neon Philharmonic.