Re: crown molding
There is no "rule" with crown, you can do it either way or even use a differing color than the walls or ceiling. It all depends on the effects you're trying to create.
Same color as the walls will visually increase the height of the walls. Same color as the ceiling will visually lower the ceiling. Using a third, or accent, color will bring the crown out and make it more noticeable in and of itself. I've used all three methods with great success, it's all a matter of the effect you're trying to create.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!