I used to use the transparant filter with compiz, just to take the edge of some glare/brightness. I even tried a sepia/monochrome filter with some success. There was an error with compiz and my system, so had to give up on it.
Then I tried a light on dark theme. As I find the terminal comfortable, but I feel you need to match it across your desktop - otherwise it's jarring. That is going from light on dark to dark on light.
It seems support for darker themes is buggy at best on Linux. To the point that recently I had to undo my dark theming just because I need regular access to one spreadsheet.
Now I have a halfway house, browser is setup for light on dark, and the rest of my desktop is greyish. Still buggy though, something as simple as Google's search box is unuasable because I've a dark font on a dark background. And so it goes on.
I might give flux a go. I've installed redshift on XFCE - but it's not currently working. Edit: okay it took like 2mins to get it up and running. Not sure what to make of it. Will see.
I've got quite used to a light on dark them though to overcome brightness issues.
It seems to work well, and if you read the description, it seems like a lot of effort has gone into matching the two versions.