Today's a very gray day with lots of white snow falling so let's 
talk gray and white....grout, that is.

I've seen a lot of great kitchens using subway tile with gray grout lately.
Alison Cayne's kitchen in the Domino Holiday issue is a recent favorite.

On my "stove wall," I'm planning some floating shelves--I put up some
blue painter's tape just to experiment with their placement--but before
that, I'm going to be installing white subway tile from the counters to the ceiling.

via Our House blog

I've already purchased my tile--a soft white with a crackled glaze--and
I've already made a decision on the grout.  But if you look at these examples
of both white and gray grout, you'll see why it was a tough decision.

Crown Point Cabinets via Houzz

via Simply Seleta
via Plaza Interior

Daniella Witte via Skona Hem

Marta Stewart

Anna Kern via Desire to Inspire
Badgley & Mischka Kitchen, Elle Decor

via Houzz
This might be a lighter value gray.

via Apartment Therapy

Are you in the white or gray court...or do you love both?