I find it visually pleasant to reverse the background and foreground colors when working on a notebook; as shown below, in fact, it's almost a requirement after working long hours on the same notebook.
SetOptions[EvaluationNotebook[],
Background -> RGBColor[0.0, 0.0, 0.075], FontColor -> White
];
However this has the disadvantage of making the text cursor (not mouse pointer) very difficult to see, I couldn't find any documented option to change its shape or color, is there any option that allows this?