Sorry, I do not understand if I am supposed to list my 20 favorite albums, or 20 albums which faithfully represent my overall musical tastes?
The Rolling Stones - Beggar's Banquet
The Beatles - Abbey Road
Marvin Gaye - What's Going On?
The Clash - The Clash(UK version)
Steve Winwood - Back in the Highlife
Traffic - Traffic
Stevie Wonder - Songs in the Key of Life
The Doors - The Doors
Brahms Violin Concerto - Gideon Kremer, soloist
Tchaikovsky Violin Concerto - Isaac Stern, soloist
Steely Dan - Aja
Fleetwood Mac(Peter Green, member) - Greatest Hits (1970)
UFO - Strangers in the Night
Iggy Pop - Lust for Life
Janis Joplin - Pearl
Beethoven Symphony No. 9 - Roger Norrington, conductor
Phil Collins - Hello, I Must be Going
Roxy Music - Siren
Swing Out Sister - It's Better to Travel
Led Zeppelin - Led Zeppelin
I didn't repeat any groups, although I repeated Steve Winwood as a solo artist and as a member of Traffic. I only listed my favorite of each artist/group. Otherwise, I would have listed more Beatles and Traffic albums.
The above are pretty representative of what I listen to on a regular basis. Punk, soul, heavy metal, R&B influenced British rock, glam-rock, 80's pop, female rock vocalists, classical music, and adult contemporary fusion. The only one I left out was Pink Floyd's Dark Side of the Moon, because I hadn't listened to it in over 15 years. It used to be one of my favorite albums. That album alone wouldn't accurately represent my musical tastes because I am not into theater/performance rock i.e early Genesis or Frank Zappa.
I had to leave out The Who's Who's Next because I needed Beethoven represented in my list. The Beatles and the Stones would represent any of the mid-late 60's groups which sang about the counterculture.
One gap was the absence of a representative African_American Blues/R&B guitarist such as B.B. King or Robert Johnson. I like what I hear, but I haven't listened to enough of that genre.
Nothing after 1987. Jewel, Kelly Clarkson, Norah Jones, etc. aren't sticking to my musical consciousness. This year's Grammys was the first one I partially watched in perhaps 15 years. Only because The Police reunited.