Music is an integral part of writing for me. I prefer to have it on in the background as I write, and I need to have music without lyrics I can understand, so I don't get distracted. My go-to music is usually soundtracks for movies I haven't seen (that way I don't associate the songs with specific scenes), and lately that has meant Becoming Jane, Pride & Prejudice (2005), and The Duchess.
While I was writing Oleanna, Trio Mediaeval's (Grammy-nominated) Folk Songs was the only thing I wanted to listen to. The album is comprised of Norwegian folk tunes, many from the Middle Ages, and it is 100% enchanting. There are samples of all of the album's songs at the link above, and you can listen to the full version of Villeman og Magnhild here.
But for me there's the music you listen to while you write, and there's soundtracks that represent the story you've written.
Other authors see soundtracks differently--which is why I hosted a podcast in 2008, Writers & Their Soundtracks, sharing the stories and soundtracks of writers as diverse as Elizabeth Chadwick, Ekaterina Sedia, Heather Domin, Jason Erik Lundberg, C.C. Humphreys, and Jeff Sypeck.
I like to create my soundtrack after the fact, choosing songs that I find representative of the story and the characters. Here's the soundtrack I've created for Oleanna.
Vi Skal Ikkje Sove Bort Somarnatta (We Shall Not Sleep Away The Summernights) by Lief Sorbye
I Mine Kate Ungdomsdagar (In My Reckless, Youthful Days) by Trio Mediaeval (which also shows up as a song Anders sings in Oleanna)
Det Star Ein Friar Uti Gare (There'S A Suitor In The Garden) by Lief Sorbye
Falling Through the Ice by The Ocean Blue
Jealous of the Moon by Nickel Creek
Stay by The Blue Nile
How Distant Your Heart by Robin Guthrie
Short Trip Home by Joshua Bell, Edgar Meyer, Mike Marshall, and Sam Bush
Hljómalind by Sigur Rós
A quick additional note: after I posted this blog entry, Jeff Sypeck suggested the album Nordisk Sang. It is absolutely enchanting, and indeed haunting. Recommended.