[jjcm]

Flux is a great first approach, but I think that something like this needs a lot more tweaking (on the hardware side as well) to become viable. The issue with flux is that it just creates a color overlay on your monitor - it doesn't actually reduce the brightness of your backlight. This is understandable because very few desktop monitors and video cards support dimming the backlight via software. This is tremendously annoying to me as a designer, because on one hand I would love to have my displays dim automatically to save my eyes (and more importantly, to save me time as I end up manually dimming each of my 3 monitors at home every night as I'm working; something that eats up a few minutes because I have to navigate through the annoying on-display menus) but sadly flux isn't an option because it reduces the dynamic contrast of the monitor as well as the number of possible colors that the display can output.

Flux works decent for reading/coding/web browsing/etc, but it needs access to the backlight levels to truly be fantastic.