I have been doing some more research on painted white fireplaces for Angela. Since her fireplace is positioned between two windows there isn't a lot of room to add a mantle on the sides.
One thing I have noticed about the best looking painted white fireplaces is the they keep a contrasting tone or color in the floor tile or interior brick.
The second observation surprised me, they all have a simple mantle. I thought you would want a large elaborate mantle to contrast the white but almost every one I have found has a simple mantle.