Most listened to artist

The Eagles

Bruce Springsteen

The Beatles

Mark Knopfler/Dire Straits

Emmy Lou Harris

Jackson Browne 

Charlie Haden

Keith Jarrett

Diana Krall

Mozart

That's ten - and I'm just getting started!

Any original pressings from Command label produced by Enoch Light 

I spent 10 min composing this nice list and since I made a great comment about the old days , the starched shirts didn't print it. Pound sand

The all-time most listened to artist in my collection are the Motown house band, The Funk Brothers.  Similar to that, some combination of Chick Corea/Dave Holland/Jack DeJohnette are on a large number of my post 1965 jazz recordings.

At different times I've immersed myself in any number of artists, but I might not listen to them that much anymore.  I still like them, but they are not in heavy rotation.  Jimi Hendrix, McCoy Tyner, Santana, Wes Montgomery, Dwight Yoakam, Larry Coryell, Jack Bruce and Lush fall into this category.

With the above said, here's my list:

The Band/Robbie Robertson

The Beatles

Elvis Costello

Marshall Crenshaw

Miles Davis

Bob Dylan

Duke Ellington

Stan Getz

John McLaughlin

Joni Mitchell

Rolling Stones

Roxy Music/Bryan Ferry

Steely Dan

Swing Out Sister

Tears For Fears

I would also give a shout out to David Baerwald.

Iron Maiden

Diana Krall

AC/DC

Yes

Rush

Steely Dan

Neil Diamond

U2 (early U2 before they got weird. Boy through The Unforgettable Fire-I feel like they changed after this album. And not for the better)

Clannad

Fleetwood Mac