What would be your favorite 3 tracks that demonstrate how great your system sounds?

That’s a tall order as we enjoy so many different types of music. Here are a few. 
Any Queen song

Ghost Rider- Make us stronger

Donna summer- I feel love 

Christopher Cross- Sailing

Warren G - Regulate 

Yes there are too many way more than practical to enumerate.  You have to listen to a wide ranging sample to fully appreciate things. 

Joy Inside My Tears - Stevie Wonder

Into the Mystic - Van Morrison

Whole Lotta Love - Led Zepp 

All selections are BluRay audio except Led Zepp, which is DVD audio.

Top Two:
Friend of the Devil, Sugar Magnolia - Grateful Dead American Beauty
Three:
'Round Midnight - Linda Ronstadt & Nelson Riddle 'Round Midnight album (or almost ANY other song on this for true vocals)

When nobody else is home, and you can really crank up your rig - try :

Money by Pink Floyd

Young Americans by David Bowie

I used to be an Animal by Eric Burdon ( Lost within The Halls of Fame 2002 )