There have been a couple studies done that showed that white text on a black background increase recall of data.
Although this is certainly debatable how might I invert the colors of Notebook font and background in Mathematica?
There are likely more then a couple ways to do this(external software vs stylesheet). Currently I think the best solution likely involves using the built in Mathematica stylesheets, but currently(as mentioned in the comments) there doesn't appear to be a great way to do such.

FontColor -> GrayLevel[1], Background -> GrayLevel[0]works for change both the font color and background but only partially. Take a look at the picture here generated from the following code:NotebookPut[Notebook[{Cell[BoxData[RowBox[{"Print", "[", "\"\<test\>\"", "]"}]], "Input"]}, FontColor -> GrayLevel[1], Background -> GrayLevel[0]]]– William Oct 18 '13 at 02:58