I think creamy white is going to be "off" with the marble which has blue/grey undertones and veining. Try Pittsburgh Paints 506-2 NEWPORT MIST or 506-3 DUSTY MILLER for a very airy watery pale tone that will let your marble and cobalt blue glass trim be the stars they should be.

Since you have little natural light, be sure to add low voltage halogen potlights (in housings and trim and lenses that are made for wet areas), a couple in the shower and one over the toilet (shining right where you would have your magazine if you're reading!!) and one shining down into the sink. Then your decorative lighting fixtures will only be needed to add style and to illuminate your face for applying make-up, brushing teeth, etc. I love using sconces at each side of the mirror which eliminate deep shadows from overhead lighting.

I would go with white towls for a spa look. Coloured towels would kill this bathroom I think! They don't need to be plain towelling--they could be waffle weave or monogrammed white on white for instance. Your bathroom does sound divine!

Cynthia,
I agree with you. It sgould be a gray white, not a creamy white. What do you think would be a good Sherwin-Williams color -- "Pure White SW7005?" "Everest White SW2137?" "Extra White SW7006?"

Hard to suggest a color without seeing the actual space, but I like the gray / blue suggestion.