Top 3 songs to evaluate a system

Fantastic topic, especially because you're asking for specifics

I'll start:

Ives, Overture & March "1776" Nordic 2L recording
Highlight: At least first 1/2 of song. High quality recording with a lot going on; great test of soundstage depth, width, instrument separation, and the ability of a system to deal with very complex transients and dynamics across the entire frequency spectrum.
https://www.discogs.com/release/4195543-Various-The-Nordic-Sound-2L-Audiophile-Reference-Recordings

Shelby Lynne -- Just a Little Lovin' (other tunes from this album also excellent)
Highlight - Thump of bass drum at beginning should shake your room, will test bass response and dynamics from the get go. Instruments have a lot of space, are very well recorded; vocals have a tremendous amount of texture. 

Keith Greeninger & Dayan Kai, Looking for a Home (Blue Coast Collection - The E.S.E. Sessions)
Highlight: Male vocals, acoustic guitar and steel guitar; startlingly lifelike recording, extraordinarily precise soundstage locations for both singers and instruments.

I might suggest a slightly different approach to this question.  It's easy to list great sounding music.  The problem being those picks tend to make most every system sound good.  I would suggest using music that has always seemed flat (for want of a better term) on one system and ask does the next system improve the sound?  Would that not better show the difference?  Just a thought.

Thanks @hilde45 for being the first. I should have added a double bonus to have song easily available.. like Spotify. I can't find two of the thee pieces proposed. But Shelby Lynne is great and it's really my style of music!

@bigtwin - Excellent point, and is indicate that your strategy is to use "flat music" to evaluate a system. Really something to think about. But which flat song do you use?