I hate hate hate (did I say hate?) staring at black-on-white text on a monitor. When your whole day is spent in front of a computer, the glare from a bright LCD screen can lead to some pretty serious eye strain. So for any tool in which I spend a significant amount of time, I tend to adjust the colors to give my eyes a rest.
As a developer working in an IDE with syntax highlighting, this can become a time-consuming process as you hunt down every last textual variant in the options. Fortunately, the kindly residents of the interwebs have contributed their time to the following websites.
If you're a Microsoft corporate sellout, check out Studio Styles (for Visual Studio).
If you're an Open Source hippie code-hugger, give Eclipse Color Themes a click-through. There's also an Eclipse plug-in for easy in-editor switching. Nice!
And for the love of Cheese and Rice, turn down the brightness on those monitors! Your eyes will thank you!