What's the soundtrack to your cardio session?

Okay, so this might be a bit of a silly thought, but it hit me during my run this morning. I was listening to some ridiculously peppy pop music and started wondering if that’s the right vibe for pushing through a tough cardio block. On one hand, that high-energy beat is great for keeping pace. On the other, sometimes the struggle feels more like it deserves a full, dramatic movie score you know, the kind that makes you feel like you’re in an epic training montage.

I’m curious what everyone else imagines. Do you lean towards the upbeat, motivational tracks to power you through, or does something more intense and orchestral match the internal drama of a long session better? What’s playing in your head (or headphones) when you’re in the zone?