In Western countries, black is associated with death and depression. Called Black Thursday, Netizens turned their pages black for 48 hours in support of the Coalition to Stop Net Censorship. To read more about this controversy look at this and this. With these reactions in mind, think about your visitors cultural associations when choosing dominant colours for your web pages. Some colours are more taxing to look at than others.
Bright colours reflect more light which sometimes over stimulates the eye.
A page with a splash of light yellow or bright orange may attract the eye, but unrelieved light yellow and bright orange will be off putting as the eye becomes tired. The eye is confused by contrasting colours. For example, when there is not much light, blue and green appear brighter than reds of equal brightness. Colour psychology is back in fashion. The fashion industry has taken full advantage of the resurgance of this.