Your most played music/song

Grateful Dead for 35 years. King Crimson, Brian Eno, Roxy Music, for 30+ years. Can for 20 years. Bardo Pond for 10+ years. 

Roon reports the top 4 of my 25 Most Played (Since Jan 1, 2015)

1- Night Ride Home, Joni Michell

2- Bright Size Life, Pat Metheny

3- Ciaccona in G minor, for Violin and Piano, Jessica Lee

4- Homecoming, Ray LaMontagne

I wouldn't have guessed any of those. Yet, upon reflection, they're all good songs. 

According to my iTune play count the most played track is "Burn-In Tones" from the Sheffield/XLO Test disc.  The test disc has 3 of the top 10 most played tracks.  The most listened to music is David Baerwald's "Wondering".  Other artist in the top 10 played tracks are Dixie Chicks, Amy Winehouse, Seal and Lucinda Williams.  Statistics can be a little misleading since my go to track is Bryan Ferry's "The Right Stuff".

Tom Waits or King Crimson, Joni Mitchell on occasion

Funny you would ask. I just finished commenting on an old thread about Mark Knopfler's "All the Road Running." I was surprised to read that some didn't like it. It has become one of my go-to CDs, out of a large collection. I think Emmylou Harris' contribution is just what the album needed.