Nitin Sawnhey - Noches en Vela (parts 1 & 2) from the album Philtre
Rodrigo y Gabriela - Triveni, from the album 11:11
Submotion Orchestra - Blindspot
...followed by the entire albums Amnesiac and Hail to the Thief by Radiohead: two of the most challenging albums I've encountered with any system. They're extremely well mastered albums, but have a lot of layers and many different tonal textures that can easily wrong-foot a system that might be able to otherwise fool you into thinking it's capable.
They should hit you with plenty of slam and speed with timing that demands you to get involved with the music, you should be able to sense each strand of sound rather than blending into a giant mess and although they should bite, they should never have you reaching for the volume button to turn it down. If your system makes you respond with 'wow' (as it should) then you've got a well-balanced system that should handle anything else with ease!