I forget whether I ever answered this one.

I sing in C almost exclusively--it about encompasses my limited voice range. There are a handful of old Gospel songs I do in G so I can use my Preacher Voice, which is *way* at the bottom of my range. And I have written a couple in D, where I wanted a real whiny sound from singing at the top of my voice range. Both the Ds and Gs are a strain on my voice, and I can't do more'n a couple without giving myself a rest.

Play? Like some others have said, I can play in any key. What configurations I use for the chords ('cause there's between 3 and 5 ways to play just about any chord), and whether I use a capo, depends on the song. If I've developed a particular pattern for a song (I will have done that for a lot of covers I play regularly), then I'll often use a capo to boost that pattern up to whatever key the singer's comfortable singing in, and we're done.

Joe