Black on white just isn't natural for CRT usage. Neither is white on grey, blue on green, anything on an imagemapped background, and so on and so forth.
White, or any other bright color, on black however, is pefectly natural and readable. Even for the 14" crowd. :)
So that's it. I'm not protesting some bit of legislature, mourning anyone's death, or partaking in any other hippie bullshit. Just trying to make your life easier.
Now Go back to that from wherest thou camest.