I noticed way back when in "Cry Wolf" that Anna (and probably Charles since he recognized the version) likes The Irish Rovers. I thought you might like to try The High Kings as well; they've also got a nice version of "The Black Velvet Band" and I'm a really big fan of harmony.
I love all your books and Charles and Anna are my current favorite characters (though I really like "When Demons Walk", too). I got a signed copy for Christmas from my aunt and it was definitely my favorite present. I've bought most of your books both in paperback and electronic so I can take them everywhere; they're the perfect fallback since I can always read them again (and again and again and. . .). I've already read "Fair Game" four times. Thanks for the endless entertainment!