I have carried out a research study into this area for my degree and have put together a section on my site that shows the colours available, both in tone and tint combinations. Emphasis is on using safe colours. There is also a section on the site which allows the visitor to interact with the different screen colours and see how they affect each other. The site is still under construction, but should be completed by the end of April. Familiarize yourself with subjects like color wheels and the emotional responses evoked by different color combinations and you'll have some powerful tools at your disposal.
Transparency is another big helper too.
For example, at one pizza store site, I used a tomato color for the main page's left navigation bar. I used black for its top navigation bar, because I felt the black background brought attention to a navigation scheme that was important but secondary to the site's intent. I rely more on textual and color-shading effects as opposed to graphics wherever possible. And I always ask for the user's input about any aspect of the site. Design in black and white, adding color for emphasis.