It might sound a little odd, but I slightly prefer programming in a harsh-on-the-eyes environment from time to time. I think it keeps one out of one's "comfort zone" and thus more focused on immediate problem-solving.

How does the joke go? -- "Hours of planning can be saved by just a few weeks of coding" or something along those lines. I find a garish eyestrain-inducing theme to incite me to spend more time planning and less time coding.

Could be interesting to make an ADHD theme...

I think I might have cracked that one... I configured my .emacs to randomly choose from a selection of 20 or so monospace fonts (filtered by local-machine availability) and ~35 different color themes each time it starts up.