I tried the black background. Frankly, I think it appeals to certain types of people. I'd be interested in seeing whether those people tend to be 40 and older who started out back in the days of monochrome or pre-Windows programming. In those days, there was a semi-hot debate (are there tepid debates?) as to whether amber monitors were better for your eyes than the standard green monitors. Frankly, this largely appeared to be driven by the fact that amber monitors were relatively rare and a bit pricier. In other words, it seemed like this was driven by the snob value of amber monitors. Of course, that was also back when a screen saver actually saved the screen, and there was also some suggestion that amber monitors burned in the images less when left on.

Once we started with CRT, the real key to eye comfort was the refresh rate of the monitor. Some people could actually use CRT displays with refresh rates down around 60Hz, but for others, the screen would be flickering like a strobe light. Some studies showed that even the people who didn't see the flicker were still being affected by it, so monitor refresh rates of 75Hz and above were pushed heavily. If you work with CRT displays these days, you can still adjust the refresh rates, and you want to keep the rate at or above 75Hz, even if it looks ok at lower rates. Now that we have LCD displays, you still have an option to change the refresh rate on your display adapter, but it makes no difference.

And with all that, the point I was headed towards was that I suspected that people who used black backgrounds were either older coders trying to look retro/cool, or younger coders trying to wear their hats at a new angle. It's just for show, but that's not to say that you shouldn't do it. It DOES look retro. When I tried it, I felt like I was back coding for DOS on a VGA monitor (had to be VGA, as I had colors that CGA and EGA couldn't handle).

On the other hand, I often start working before the sun comes up, and I don't need the lights on when VS comes up, since the vast expanse of white background provides sufficient lighting for my typing. That may very well strain your eyes.