Side note about f.lux. I installed f.lux on my windows XP laptop and it kind of messed up the settings. The funny thing is even after uninstalling f.lux, my laptop retained the brightness settings that were set by f.lux. (Thankfully, it is fixed now.) It also crashed a few times due to its memory consumption.

Issues highlighted in the FAQ page here. http://stereopsis.com/flux/faq.html