"Ghost Riders in the Sky" reminds me of a particular encounter with . . . well, ghost riders in the sky, actually. I even used the song to convey the scene, but though this sounds really cheesy, even to me, it wasn't. The players and their characters were all really wigged out. Great session.
"In the Hall of the Mountain King" is the perfect theme song for Dwarven Armies on the attack, the way it slowly and methodically builds to an insane fever pitch. (I'm speaking, of course, of the classical piece. There's a pop song by that name too, I believe, but it's all about Grieg [sp] to me.
"Ride of the Valkyries" R.Wagner. 'nuff said.