In the DFW area we have ones with blue letters, ones with green letters, and even some with red letters. Sometimes it seems like they are making an attempt to match the brick and/or architecture. The one I know of with red letters doesn't look very attractive to me, though. The paint on the building is kind of pinkish, and the red looks ugly with it.
I bet they start making more green ones now since it is "in" to be "green". That's okay with me, though. The green letters on a tan to brownish brick make the most attractive stores aesthetically.