Sometimes the 'flat keys' - F, B flat, E flat (1, 2, and 3 flats respectively) sound good on the fiddle, particularly in slow moody tunes such as slow airs. And they are no harder to play than D and G IMO. The worst key to play on the fiddle IMO is E major where you can't play the open D string, but have to sharp it with the first finger. Why do singers who play guitar like to capo up two frets and play in D chording which then comes out in E?

S. in Seattle