The Reforming Baptist has an excellent post about how theology affects the mood of Christian music. Read about it here. His categories and descriptions are spot on and actually mirror what I have been trying to communicate myself for a couple years.
One of the biggest reasons this discussion is necessary is the distinction he makes between “mainstream” Christian Contemporary Music (CCM) and new CCM. This difference is not only significant, but crucial to understand especially for those interested in planing and leading a worship service. It is this same distinction which makes John Frame use the term “Contemporary Worship Music” to differentiate between these two general realms of Christian music. I would recommend his book on worship here and his book focused on music here.