Amber on black makes me feel really comfortable, so that's how i set up mine
When I was 6 to 8 years old, the library at my school had monochrome terminals with amber text, and the library back then was so comfortable and quiet, so I have always associated amber on black with that nostalgic comfy feeling
Slightly OT, I remember a non-crt, the Toshiba 5200 (which was more than a laptop a transportable as it needed mains connection), plasma screen that had a distinctive (slightly darker than amber CRT's) orange that was very readable.
When I was 6 to 8 years old, the library at my school had monochrome terminals with amber text, and the library back then was so comfortable and quiet, so I have always associated amber on black with that nostalgic comfy feeling