Bass. All the bass.

Guillaume David's superb Children of the Omnissiah, played back at half speed and an octave down. This will absolutely test the bottom end of your sound setup; you need to use good headphones or a staggeringly expensive speaker setup, or preferably both. If your windows aren't rattling you're not doing it right. Trust me on this.

(Yes, there are some artifacts towards the end. Shifting the pitch down moves normally inaudible supersonic noise into the audible range and even the FLACs I managed to track down had artifacts. This is one of the few situations where high-resolution audio would actually be worth it,)