I've always been a musically inclined person and over the years music has transformed for me as less of a form of entertainment than as a means of attaining higher awareness or as an aid for meditation. The Hindus see the importance of this with their so-called Nada Yoga, which beyond listening to one's "inner sound" also includes the use of music and chant for spiritual purposes. The same could also be said of the Sufis and Catholic/Orthodox liturgical music and chant. Really I can't think of a major sacred tradition that is entirely music-less.
Personally I really enjoy the aesthetics of the Chinese guqin, which has been used by Taoists and also apparently by Chinese Buddhists for spiritual cultivation, and I am attracted to learning it for the same purpose. On Guan Pinghu's wikipedia entry it states,
He also studied with the leading players of three different schools; Yang Zongji (1865–1933), the leading player in Beijing, the Daoist Qin Heming, and the Buddhist monk Wucheng.
A search for "Buddhist monk guqin" on Google turned up with this webpage stating that Buddhist monks play guqin and showing what appears to be a Western monk playing one:
http://paramita.typepad.com/dharma_fore ... index.html
Are these individuals breaking their precept? Are these rules just not enforced?