In my opinion, color on screen should be used very carefully, perhaps more carefully than in print. I say this because, until color e-Ink is widely affordable, screens will be backlit for the foreseeable future. What this means is that since screens are backlit and since colors made from light instead of pigment are more intense by default, the colors are typically more intense and bright than they would appear on paper.
You might be able to replicate 100% green with a fluorescent ink, but metallics have to be faked somehow.
It also means ultra-bright colors can be a bit garish. (Remember the color-clashing phantasmagoria of Geocities sites? Yeah, you don’t want that.
Since you don’t want to hurt people’s eyes when they arrive at your website, it’s a good idea to start with a neutral palette and add color in small doses. If the color is too intense, it’ll “burn” your eyes. If you need a refresher, go see the Geocities-izer again.
Also, reversed-out type is generally hard to read on screen (unless you’re in a darkened room, and even then, 16 pixels is probably the absolute minimum smallest size you can set reversed type and not cause eye strain.) If you have areas of intensity, you want to be sure to provide plenty of relief for the eye.
That’s why when I designed this site, I set out to use a fairly neutral design, added the orange and silver from the logo sparingly. The headlines in black would be too much contrast, so they are silver to ease the tension. Furthermore the limited use of color on the site helps the portfolio pieces stand out.