For me it really depends on the niche of the site whether I use light or dark tones. Once I have figured that out I will go ahead and pick a group of colors to work with. Ex, going with a darker background I will choose a vibrant overtone such as oranges, yellows, greens, cyans.
But as I said in the beginning.. all has to do with the content of the site.. sites about organic fruit... most likely I will go with a light background, and earth tones (tans,greens,browns,grays)
I keep a swipe folder... samples of sites that I've seen in my travels that I think are appealing to whatever the target audience is. When I want to build a new site, I look through the samples to get ideas, colors etc.
I plan ahead on paper real quick - choose 2-3 color that compliment each other well (black or white are usually a given color) Dont use gloomy color or colors that dont contrast well together...
For me it also tends of the niche. If I am building a client site I use the color scheme of the literature I collect from them letterhead, business cards, etc.
I made a short entry at IntelBank about the Psychology of Colors in Business. This might apply to Websites as well. As a matter of fact, i used distinct colors for IntelBank.
Subtle gray, minor white, black and green as the leading colors for logo, branding, delivery and presence.
Choosing your colors will largely depend on your target audience. Certain color schemes leave different perceptions in different target groups.
It's all how one's imaginations flow! Several factors must be considered while deciding colors of websites. The niche of your site is important.
But Remember to do lot of research before finalizing the colors. This is because, In many cultures, colours convey meanings. These meanings may differ from one culture to another.
If you choose a colour which has a negative connotation in a geographic region where you assume a large proportion of your potential online customers to reside, you may miss out on repeat visitors.
As an example, in Australia and the United States, the colour white is associated with happiness and purity, whilst in the Far East, white resembles death and mourning. In many Latin American countries, death is resembled by the colour purple. The colour red is considered positive in Denmark, Romania and Argentina but has a negative or unlucky meaning in Chad and Nigeria.
For these reasons, it is always recommended that research be undertaken prior to commencing a website's design so that it can be adjusted accordingly.
This is very important while targetting International visitors.