I was going to call this "Writing Music" until I realized that could be taken two ways, and wasn't necessarily what I meant :-).
As Cheryl and Margaret mentioned in previous posts, I also write with pictures nearby. I try to find pictures of my characters (or close to what they look like, in some cases), and also any pictures that capture the times, the places, or the feel of my story. These often act as my touchstones, keeping me grounded in my story when I'm stuck, or having a tough time making the mental journey back in time.
Just as important to my writing, however, is the music I write to. I have a small collection of cassette tapes and cds that I constantly play in the background while I write. Many of them are movie soundtracks (talk about some dramatic stuff!), but I also have some with vocals. Generally if I can hear the lyrics clearly, the music distracts me, but there are several vocal artists whose work actually helps me stay in the mood and "in character."
At the top of that short list is Loreena McKennitt. The music is wonderful--it flows over and around me as I write; it's evocative and emotional. It also, imo, captures the flavors of the past, very important to a historical romance writer. The lyrics are often from the past, as well--"The Highwayman," "The Lady of Shalott," "Bonny Portmore," to name a few.
Works for me :-)
At the moment I'm back in the medieval era, so I've been playing the soundtracks from "Kingdom of Heaven," "Tristan and Isolde," and "King Arthur," along with Loreena McKennitt's 2-cd set "Live in Paris and Toronto." I may switch out several of these soon, or dip into my stash of cassettes, for the soundtracks from "Last of the Mohicans," "Robin Hood," the two recent "Zorro" movies, or "Gladiator."
I look on the music as a type of soundtrack for my writing. When I hear it, I get into work mode--it's time to write. It's also helpful for brainstorming.
I've been tempted at times to include composers and artists in the dedications for a couple of books. They've certainly helped me get from blank page to finished book!