Okay, so there is a lot of discussion over music and role play gaming around the net. Personally, I've never used music with my games as a DM. But not because I don't want to, but because the technology just wasn't there. In the olden days it was harder to find music which was right for gaming and most of that time I didn't have a sound system to play it on anyway. Having music during play would have meant constantly turning a cassette tape over about every half hour. It would have been more distracting than uplifting.
However, about ten years ago I was in a D&D 2E game run by my friend Rob in England. Rob was the first GM I ever saw who actually included atmospheric elements in his game. He always had "epic" music playing in the background. This was mostly movie sound track music--something I hadn't considered before. The music was suitably atmospheric and also, importantly, instrumental. I think that playing songs with vocal lyrics would interfere with talk at the table at odd moments--with the possible exception of lyrics in languages you don't know. I have a lot of music on my mp3 player which is not in English and I find it less distracting when driving or writing. Rob also had the lights down and candles here and there around the room to add a great medieval feel, but that's a post in itself.
Today I still think about adding music to my games but I still really don't have a sound system up to the task. I think that you really need something playing nearby at a low level but with enough quality of sound to come across even at low volume. Currently I only have small computer speakers and that won't cut it. The other thing you need is "epic" music. Luckily, there's YouTube to the rescue. Just search on "epic music mix". There are lots of very long mixes (1 to 4 hours) with terrific epic instrumental songs seamlessly blended together.
So if I ever get a proper sound system I'll cue up some epic mixes in the background with my games and kick things up a notch.