Twenty years ago Wenatchee The Hatchet had no fondness for or any interest in either rap or country. Now, well, while overall they don't rank as the favorite musical styles of WtH Hank Williams Sr wrote many a fantastic song. Country from people born before 1960 has proven to be pretty amenable to WtH's listening habits. "new country" is a poor substitute for old rockabilly, at least so far, which is not to say there's not some superb newer country out there.
Rap, well, not quite as many artists have stuck with WtH and for the reason that if you opt to specialize in chamber music for classical guitar that's not explicitly Spanish there's a lack of overlap in domains of exploration. Tunes are also nice to have when possible. A few tracks from Lauryn Hill and Cee-Lo Green have proven pretty memorable but it's a genre I haven't gotten around to much.
On the other hand, if we interpret and apply Galatians 3:28 and Colossians 1:19-20 with an appreciation not merely for groups of people but the kinds of music they create, then what we may have an opportunity to observe is that there is not exactly a "church" style of music but that all musics may properly appear within the life and activity of the church. Wenatchee The Hatchet wrote a guest piece for iMonk back in October 2012 touching on the subject.
Do we say "You are welcome to share in the fellowship of Christ with us, but your musical style is not?" This is not so much a matter of whether everybody's going to enjoy the same stuff, and there's no doubt reason to worry that as Christian pop music essays have suggested in the last thirty years that an attempt to "redeem" a musical style may often "redeem" it to the lowest common denominator.
On the other hand, it seems like a fully-orbed understanding and application of Gal 3:28 and Col 1:19-20 suggests that musical styles can be brought into the fold.
And it's not like the major/minor key system so often taken for granted by regulative principle fanboys who don't want certain styles of music showing up in church has even existed for a full two centuries in "common practice".