Changing my response, after seeing the above:
In a smaller home, I think you should leave the whole ceiling, including all tiers, white. In a mansion, such as those linked above, you can be more creative, but I still think you should always leave the first tier white.
Look at any high end decorating magazine, and you will see that most ceilings are white, and ceilings and tiers and mouldings are usually painted the same color.
If you paint the ceiling a partially different color, it will become a focal point. It depends on the rest of your decor, and the size of your room, whether you want your ceiling to be a focal point. If you have elaborate decor in your room you will want to keep your ceiling simple (all white). If your room is more spare, you can do more with your ceiling. If you have a lot of artwork in the room, you probably want to keep the ceiling simple as well, and all white.
Check out Architectural Digest, for one. Most of the ceilings in AD are pretty elaborate.
I think you should add a little gloss to your ceiling, as well. Use eggshell or satin paint, vs. flat. It's really beautiful that way.
Do paint swatches first, because whites can be really different, and some whites are really ugly! You want a rich, creamy, lovely white, not a greyish, dismal one.
Have fun!