I like to paint the crown molding a different shade than the ceiling so that it's more visible. Crown molding is a nice feature that you're paying for--you want to see it! My trim colors are often B1 or B2 (one or two drops of black in a white base) or Alabaster, gloss finish (or high gloss--my clients love that one).

There are no rules - What works for you?
As decocco hinted at - If you're going to have it, you might as well show it off! Just make sure that the crown moulding is the same color as your other trimwork for continuity.

Thank you. I have this figured out. I did a light taupe for the ceiling and and a darker taupe for the walls and white trim. Pictures when done.

That sounds great!