I have 500+ gospel CD's and about 6600 MP3's on my computer, and a few years back I did a survey of hundreds and hundreds of gospel songs to see what key they were in. This is what I found (I thought it was interesting). The keys are list in order from most popular to least popular.
1. Ab
2. C#
3. Eb
4. F#
5. Bb
6. F
7. C
8. G
9. D
10. B
11. E
12. A
Notice that the BLACK keys are the top five, and the keys of D, B, E, and A are the bottom four. Also, F is the most popular WHITE key, and what was interesting to me is the the key of C is not nearly as popular in black gospel recordings as one might think.