In short, it's all a matter of taste. Some people like ceilings to be white, period. Some like ceilings a lighter or darker shade of what the walls are painted or the same as the trim. Some like white or ivory trim, others experiment with different trim colors. There's really no right or wrong choice (unless you have a period house and want to be true to the colors used in that period).

Something to keep in mind: If you have an open floor plan, you can tie everything together with the same flooring, color of trim or coordinating wall paint.

Look at pictures in the Photo Galleries (see link at the top of the age) to get ideas of what kind of paint colors you like for walls, trim and ceilings.