That sounds very pretty. I would definitely paint the vanity in black, and for wall color I would lean towards something soft like a light aqua or green (not sage but more of a celery or kiwi) or even an almond or toasty brown.

I agree with lukkiirish, except for the almond/toasty brown. When we remodeled with white/gray carrara floor I thought a warm color like beige/brown/almond would look good, too. But the "paint lady" at a local paint store mentioned that the brown in those colors would make the white carrara marble floor tiles look yellowish (because they indeed have some little yellow in it that is not obvious when held next to other colors). She recommended a warm light green or blue or cream yellow. Pick some paint strips and try for yourself, maybe your carrara does not have any yellow in it.

I don't know if this is what you were thinking but I remember a few baths with the white subway tiles /carerra type tiles being posted. mrslimestone inspired a few posts

http://ths.gardenweb.com/forums/load/bath/msg0319441819578.html

http://www.thathomesite.com/forums/load/bath/msg012209551130.html?25

http://ths.gardenweb.com/forums/load/bath/msg0218220810259.html

I also thought I saw this inspiration picture posted here for someone's bathroom but it was easier for me to upload the picture than figure out where I got the picture from. The paint in the inspiration picture is Benjamin Moore #1564 Beach Glass

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