One other thing it *could* be (the difference in the way you see it and the way I see it), then, could be the adjustment of your monitor. If it's at all tilted, or it's sitting higher or lower for you than mine is for me, the color is either darker or lighter. I know that as I scroll, my colors look darker toward the top of the screen than at the bottom, and that's even with the monitor not tilted at all.
I went and looked at this at home at the two computers I have at home -- a downstairs lap top and an upstairs computer. And both this thread and my screenshot are charcoal grey on both.
Argh!!! I declare myself officially stymied!