I think the middle one (Agreeable Gray) would be a great contrast without going too dark.

When choosing the wall colour, be sure to look at it closely with your countertop selection to make sure the colours work with the veining. Cambria's Tourquay is great because it has both grays and taupes within it so you can go in a couple of different directions. If you don't mind me making a suggestion....I recommend doing a subway tile as oppose to marble so it's not competing with the Tourquay counters. Marble is stunning, just bear in mind that it is not very forgiving for splashes/spills. Kitchen looks like it will be very functional with plenty of counter space!

My remodel is the same style.. I used the "Sea Salt" color on the walls, with white cabinets and Cambria black on the countertops.. My adjoining living room has the Torquay on the hearth..