worship renewal: what's the purpose of special music?

We're currently discussing the idea of "worship renewal" at our church.  I think in the few sessions we've had, this has already led to some wonderful revelations about the purpose of worship and how/when we experience it.

In our latest meeting, the topic of "special music" came up, specifically in regards to music that is presented that isn't serving any sort of liturgical or even transitional purpose.  In most churches this manifests itself as the "anthem" or "special music" or something along those lines.  The music is played/sung while the rest of the congregation listens (or not).

This is different from, say, the offertory (the music fills the space of time it takes to collect the offering) or the prelude/postlude (people are entering/leaving or transitioning into/out of worship during the music.)

So what is the purpose of this music?   Does it give us time to reflect like the reading of scripture?  Does it expand our thinking about God like a sermon?  Does it lead us to meditation like prayer?   I don't have the answer, but I feel that what it often does is put the service on hold.

There are times when this special music ties in so well with the theme, scripture, sermon,  or prayer that it seems to flow naturally as part of the service.  But I would say that a good portion of the time it seems tacked on.  It's simply there because, "that's where we always have the anthem" or "we need a second piece of music to fill the service."

What we discussed was trying to discover ways that this time can lead to active participation as well, for those who want it.  Perhaps this is a time where we invite the congregation to consider their contribution to the church's mission during the week.  Or maybe we have some sort of ritual (remembering baptism through water, lighting a candle for a loved one, etc.) and the music then provides a accompaniment to that action.

I'll post some results once we give it a try.