Best song for immediate impact when presenting or testing?


I, as most of you, have my regular tunes that I play or listen to when trying out a new system or playing music for friends. My current starter is 'Feels like Rain' by Aaron Neville. It engages me immediately because I love it so, but it is also very well recorded and has a bass voice doing backup which in the right system has a real visceral impact.

I was at an Audio shop recently, listening to my standards, and wanted to show the sales consultant a piece that he might not have heard. I played 'Golden Rust' off the Miles Gurtu album. After about 30 seconds, he pulled out his device and added the song to his favorites. I asked why did he add so quickly, and he said that the opening electronica had a three dimensional stereophonic quality that made a remarkable impression right off the bat. I paraphrase lightly; that was his comment.

What pieces do you play of any genre that have an immediate impact, especially for people listening to a good system for the first time?
128x128cmjones
I had a lot of fun listening to the first half of this list last night!  In particular the 17-minute Dave Holland track melted my face into a puddle on the couch.  Weather Report surprised me by holding my attention for 7+ minutes of fairly "out" sounds.  And I'd never even heard of Malcolm Arnold (classical isn't my wheelhouse) but the Keith Johnson recording was typically sublime.

When I'm demonstrating the system to someone uninitiated, I explain that we'll progess like a wine or beer tasting -- simpler fare to start, palate-wreckers at the end.  So I'll lead off with Getz/Gilberto "Girl from Ipanema."  They all know the song; it soothes the ears and the mind. A couple of minutes into the track, when Stan starts to blow, they're usually hooked.  

After that I might toss out mid-tawdry chestnuts like 
Paul Simon -- Rhythm of the Saints -- "Can't Run But"
Muddy Waters -- Folk Singer -- "Country Boy"
Sonny Rollins -- Way out West -- "I'm an Old Cowhand"
Steely Dan -- Gaucho -- "Babylon Sisters"

Once I've connected on any of these, I'll just hand them the iPad and let them drive to their heart's content.  They'll eventually play their favorite Black Keys track, then look at me with sad eyes to ask why it sounds so bad.  We'll talk for a minute about dynamic range compression.

We might eventually bring the house down with something like
Sara Bareilles -- Brave Enough -- "Goodbye Yellow Brick Road"
Yes -- Fragile -- "Heart of the Sunrise" or
The Bad Plus -- Give -- "1979 Semi-Finalist." 
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Don't need immediate impact, just want something detailed, clear that allows me to really experience the sonic properties of what I'm testing.  My favs include:

Almost anything by SADE
New York Serenade by Bruce Springsteen
Summer Madness by Kool and the Gang
Symphony No. 2 Op. 27 III. Adagio: Adagio - Rachmaninov (quiet but engrossing)
Samba Da Bencao  by Bebel Gilberto

MacArthur park by Richard Harris. If your system can make that sound listenable your good to go....
So many so cool in different ways but my latest is Harmonix by Surfer Blood. The guitar lead is clean yet piercing and grabs your attention right on through from the start .