Mine's been solid black back since 1986 :)
It was staggerging to me just how much easier it was to stop, breathe, take a moment to change my mind about the fact that some config needs changing, and instead just say "it's good enough".
I tried black, but it's easy to confuse for the monitor being off since I don't have any fixed elements on the screen.
*: Window Maker is a window manager under X11 with a NeXTStep-look-and-feel.