The separation between 'profane' and 'sacred' lies FIRST in the text. May seem obvious, but that's the first screening.
Next we use connotation. This is a little more amorphous--but in essence, if the style of the music is closely associated with the "non-worship" world, then it's likely 'profane,' and not appropriate.
It's sort of like some other standards--if the 'average' man on the street thinks "American Idol" when hearing the music, it's profane. "Idol" isn't always the question, however--sometimes it is much more subtle. I've heard very good progressive jazz played in the Church. It's simply wrong--and the individual who did it SHOULD know better--but that's 'profane.'
Hassler's Missa Secunda's Kyrie is definitely a dance tune, but one has to listen very carefully to hear that--thus the 'average man' would not think of it as "profane."
The concept of "sacred time, sacred space, sacred language, sacred music" is very useful. In fact, the church and all that goes on inside the church should not be 'of this world.'