on my radar: painted ceilings

Some designers swear by painting the ceiling a different color than the walls, and I have to agree with this philosophy. I'm particularly fond of the combination of cream walls and ceiling painted in the lightest shade of blue.
Source: Veranda | Photography: Melanie Acevedo
Source: House Beautiful | Photography: Francesco Lagnese
What do you think? Would you paint your ceiling a different color than your walls, or do you prefer to keep them the same color?