A Tribe Called Quest, Aretha Franklin, Astrud Gilberto, The Band, Belle & Sebastian, Bill Withers, Billy Joel, Björk, The Blue Nile, Blumfeld, Blur, Bonnie Prince Billy, Burt Bacharach, The Carpenters. Curtis Mayfield, Daft Punk, David Bowie, David Sylvian, Del La Soul, Depeche Mode, Derek & the Dominos, Destroyer, Diana Ross & the Supremes. Dire Straits, The Divine Comedy, Dizzy Gillespie, The Eagles, Earth Wind & Fire, Element of Crime, Elton John, Elvis Costello, Ennio Morricone, Erykah Badu, The Felice Brothers, The Flaming Lips, Floex, Fank Sinatra, Georges Delerue, The Go-Betweens, Henry Mancini, Interpol, The Isley Brothers, The Jackson 5, James Newton Howard, Janelle Monaé, Janet Jackson, Jeff Buckley, Jerry Goldsmith, Joe Hisaishi, John Barry, John Lee Hooker, Joni Mitchell, Kate Bush, k.d. lang, Ko Otani, Koji Kondo, Kraftwerk, Lalo Schifrin, Marvin Gaye, Massive Attack, Mercury Rev, M.I.A., Michael Jackson, Miles Davis, Moderat, Mogwai, Moloko, Mono, Neil Young, New Order, Nick Cave, Nine Inch Nails, Nino Rota, Nobuo Uematsu, Owen Pallett (aka Final Fantasy), Paul Simon, Pearl Jam, Pet Shop Boys, Petar Dundov, Peter Gabriel, Pixies, Placebo, The Police, Prefab Sprout, Prince, Queen (ha, right after Prince), Quincy Jones, Radiohead, Randy Newman, R.E.M., Rickie Lee Jones, The Rolling Stones, The Roots, Ryan Adams, Ryuichi Sakamoto, Sade, Sammy Davis Jr., Scritti Politti, Sigur Rós, Sly & the Family Stone, The Smiths, Steely Dan, Stereo MC's, Stevie Wonder, Supertramp, Talk Talk, Talking Heads, Tears For Fears, The Temptations, The The, Thomas Newman, Tom Waits, U2, Underworld, Van Morrison, XTC, Yo La Tengo, Yoko Shimomura.
List compiled with the help of the app browser of my Sony HAP-S1 (a pretty unique compact audio system which doesn't support local streaming - on purpose, it's meant to be a standalone hifi device which works without streaming from a PC/NAS - but supports Spotify and vTuner as addition to the local music on the harddrive).
According to the statistics the app shows me, at the moment I have exactly 10.875 songs from 1.843 artists on the harddrive of the system, the songs are imported from the CDs I bought over the years and from my iTunes purchases.
Those above are my most favorite artists based on number of songs owned and individual artist playtime. I don't want to narrow it down to 10 or even 25 most favorite, it would be too hard.
Not included in above list are my most favorite composers of classical music such as Bach, Beethoven, Händel, Mozart, Haydn, Mahler, Tchaikovsky, Chopin and other usual suspects, as the device shows classical music based on name of interprets (conductors, orchestras, pianists etc.), not name of composers.
I hope this post doesn't break the thread. 
