Oh, yes, DeLint is good. (Moonheart wasn't his first book, btw, at least I don't think it was. He wrote under another name also, like Dean Koontz.)
The Songkiller books are out of print, but you can probably find them online somewhere. I read the first one and half the second, and never did get to find out what happened.
Another suggestion, and only a suggestion, would be Knight of Ghosts and Shadows by Mercedes Lackey and someone else (can't remember the other person's name right offhand.) There is a series, and they were cute.
War for the Oaks by Emma Bull (magic and music there, I read mostly fantasy, good book!)
And Manly Wade Wellman--well, I have all but one of the Silver John books, and reread them at least twice a year. I love those books. Still find duplicate copies occasionally, too.
I'm sure I'll think of more, so I'll post them when I think of them.
Just got back from the RenFaire and I'm tiiiirrrrrreeeedddddddd