There is so much more to be said about Celtic spirituality and music, that I couldn't stop with one post on subject. If you visit Celtic Christian Tunes, you'll find artists' links, reviews, and more. I found more Celtic Christian artists than I knew existed. Like David Fitzgerald, Troy Donockley, and Lianna Klassen. There are many more there I haven't explored.
I download songs to my iTunes and play them while I'm writing. The music quiets my mind and helps me to ready my spirit for what it is I'm supposed to write. I suspect many writers are the same. For me, it's Celtic tunes that inspire me the most. Vocals are fine, but words get in my way while I'm trying to get down my own words. So instrumentals are my favorites. You can learn more about these special instruments here.