If I'm auditioning on an unfamiliar system, I use CD's:
Ray Brown, et al, Superbass, "Bye, Bye Blackbird" (Telarc, 1977)
John Clayton on the left, Ray Brown in center, Christian McBride on the right; all with different bass styles. Great live recording, well recorded
Bebo Valdes and Cigala, Lagrimas Negras, "Lagrimas Negras" (RCA, 2004)
Great for piano, male vocals and bass texture.
Marcy Playground, Leaving Wonderland...In A Fit Of Rage (O2 Records, 2009), "Devil Woman" and "Gin and Money"
Well recorded rock CD. Especially good for guitar.
Tribalistas, Tribalistas, "Carnavalia" (Phonomotor, 2000)
A contender for the greatest MPB album of all time. Great for soundstaging and system 'drive'. Can the speakers resolve the three unique voices? A personal desert island disc.
Arturo O'Farrill, Live In Brooklyn, "Vieques" and "Footprints" (Zoho, 2005)
Outstanding live recording of terrific piano trio. Very intimate sound. Dafnis Prieto's drum set is especially well recorded.
Maria Rita, Samba Meu, Any track! (WEA International, 2007)
Excellent recording of female vocals. Her backing band is terrific. Bonus -- I like looking at the insert photos
The Bad Plus, These Are The Vistas, "Smells Like Teen Spirit" (Sony, 2003)
Is the trio playing together or do they sound like they are wanking around on their own? A great test of speaker/system dynamics.
If I'm auditioning on my home system, I use vinyl:
Duke Ellington & Ray Brown, This One's For Blanton, "Don't Do Nothin' Till You Hear From Me" (Pablo, 1972)
Solo piano and gorgeous bass.
Calexico, Carried To Dust, "Slowness" & "Bend To The Road" (Quarterstick, 2008)
Very atmospheric and a good test for instrumental/vocal layering.
Count Basie, Farmer's Market Barbecue, "Way Out Basie" (Analogue Productions 45 rpm/Pablo 1982)
Great for brass and brushes.
Robbie Robertson, Robbie Robertson, "Somewhere Down The Crazy River" (Geffen, 1987)
Sound staging width and depth.
Gerry Mulligan and Ben Webster, Mulligan Meets Webster, "Chelsea Bridge" and "Cat Walk", (ORG 45 rpm/Verve 1959)
Baritone and tenor saxophone tone. "Chelsea Bridge" should give you goosebumps.
Opeth, Damnation, "Windowpane", (Koch Records, 2003)
Excellent test for drums, especially cymbals. Great acoustic guitar and bass. Another great test for dynamics.
Great Jazz Trio, Direct From LA, "Night In Tunisia", (East WInd/Nautlis, 1978)
Tony Williams' drum set should be in the room! Great test of dynamics.
Cat Power, The Greatest, side one, especially "The Greatest" (Matador)
Great for female vocals. Well recorded backing band. Should be able to visualize (fantasize?) about Chan...sigh
Sarah Vaughan, After Hours, "My Favorite Things" (Roulette, 1955)
My ultimate test for female vocals.