I feel you on the country music thing. Being here in the South though, it's kind of hard to escape, haha.
And are you saying 6 minutes is short or long? Because most of what I listen to averages at about 10-15 minutes per song. Mindcrime knows what I'm talking about.
To answer the thread's question, yup, I definitely have the music going in the background. Too boring otherwise. I usually mute it when testing the map, but once I'm back in Hammer, it gets turned right back up. Yes, Genesis, Dream Theater, Spock's Beard, The Flower Kings, Phish, Marillion, Rush, on and on... It's gotta have depth, or I get bored of that too.