I find using f.lux helps with some long-term eye strain on already "good" displays, but won't make a "bad" display "good". But because of recent strides I've made I can use bad screens much more easily as well.
I do programming and writing mostly so I don't need precise colors, just have f.lux set to auto-disable for Photoshop and such.
Also of note: CRT's have much less blue light than LCD's.
Wonder how OLED screens fair in that department.