What Are Your Reference Discs? or Specific Reference Tracks

Making a list asap.

Linda Ronstadt singing "When You Wish Upon A Star" with Nelson Riddle and his orchestra on the album "For Sentimental Reasons" recorded and mastered by George Massenberg.  

I like albums that are a bit "difficult." In other words, ones that are somewhat difficult to reproduce cleanly. Rickie Lee Jones's Pop Pop can peel the skin off your ears until you get it right. The bass on Holly Cole's Temptation album of Tom Waits covers has a bass line throughout that is full, but really challenging in terms of detail extraction. Patricia Barber's Companion album challenges with sibilance, soundstage, noise floor, bass detail and dynamics. Then there are cuts that are better than you would think--examples include Magnificent Seven by The Clash, Radiohead's Creep, and Lou Reed's Walk on the Wild Side...

Here are a few of my go-to recordings for evaluating a new tweek or equipment upgrade. I also find myself listening to these recordings all the way through for pure musical enjoyment:

Jo Stafford "Ballad of The Blues." (original six-eye Columbia stereo)

Norman Luboff Choir "But Beautiful" (original six-eye Columbia stereo)

Dave Brubeck: "Jazz Impressions of The USA" (Mono - never released in stereo.)

Sue Raney - "Sings the Music of Johnny Mandel." With the Bob Florence Trio. "Discovery Records."

JOHN WILLIAMS-Paganini Guitar Trio & Haydn Guitar Quartet Columbia1968

Frank

I listen to a lot of things, but in the spirit of your "new gems" search, two tracks that I've been testing with as I've been moving my system around various apartments this year are 
1.) "Afterglow" by Lydia Ainsworth (from Darling of the Afterglow) (Tidal HiFi) It has these amazing bass synth swoops that are either killer or missing depending on whether I've got the placement and decoupling right, and her layered vocal and stray percussion accents are so forward that it's a great show of mid-high balance.
2.) "If You Could Read My Mind," by Gordon Lightfoot (Tidal Master) goes all the way opposite with natural, close mic'd guitars, baritone voice, string orchestra. Lots of separation of instruments. 
Enjoy!