The most recent figures that I found show a U.S. average range from $40k to $63k for a full-time minister of music.
That's what my title is and I'm definitely on the low end of that range and my job duties include a LOT of non-music related responsibilities including taking care of all computers, all phones, all IT, all fax and printer care, all audio/video systems in the facility, all sermon CD duplication including art/print design for sermon series sets, some hospital visits, and other assorted things that need to be done 'cause we're a small staff trying to take care of a large church.
For years I served in music ministry, both as a player and as a leader, and got anywhere from no compensation to a little compensation to a fair part-time comp and now what I earn today for working full-time.
IMHO a church should rightly compensate those whom invest a good portion of their lives into the ministries of said church as their budget allows and be realistic about what it expects in return for those who can't serve full-time.