Listened to all the songs listed.
Very difficult to choose. Fantastic entries.
What stood out to me for the only reference disc I own (2014 w/thanks to BarryG for the copy) the first time I played it on our system was the uniqueness, sometimes familiar, and breadth of songs which allowed me to both enjoy my system and at the same time get the "jaw dropping" factor when playing for others. I was also proud to play it on a dealer's $300,000 system w/ the variety and quality of the audio.
Many songs on this list qualify for the above but I was able to narrow it down to 5 which (IMHO) easily stood out for a 2017 reference disc based upon the comments above.
# 6 "Fearless" by Pink Floyd on 'Meddle'
# 14 "Man in the Long Black Coat" by Bob Dylan on 'Oh Mercy'
Man in the Long Black Coat
# 23 "The Pepperland Suite" by George Martin on 'In My Life'
# 29 "Until I'm Dead & Cold" by BB King on 'Indianola Mississippi Seeds'
and finally
#33 "You Want it Darker" by Leonard Cohen on 'You want it Darker'
Runner's up if there is room
17, 30, 28, 25, 7, 9, 13, 15, 24, 8, 10 in order of preference for the reference