The Bethesda Blog has been updated with an interview with Fallout: New Vegas' Audio Director Scott Lawlor:

"What's the coolest sound in the game right now?

I am a fan of subtlety so some of my favorite sounds in the game are all the small details in the ambiance as you walk around the wasteland - from the sounds of animals and bugs in the brush, to creaking electrical towers and distant screams and groans. These sounds all seamlessly blend with the music to create a very creepy and dynamic experience."