I love those long floorboards/wood-look tiles and they are the feature so you wouldn't want something too busy on the walls... personally I would go with a larger format say 300x600 rectified edge white tile with a matt finish for the Hamptons look... what's your vanity?... a timber one would tie in nicely with the floors and all the white... very Hamptons :)

Try googling 'Kitchen and Bathroom Resurfacing' to find a professional in your area that can respray the tiles for you. They remove any fittings that need to be removed and put them back when finished, they will fill any holes before spraying and if you want a true white colour, theirs will stay true white (not go yellow) because they are properly UV stabilised. They use a product that sets super hard, they're cheap and they guarantee their work! No, I don't work for them, or know anyone that does, but I have friends that have used them and have been thrilled with the end result.

also will give illusion of a bigger bathroom if you use bigger tiles ..I used small ones on one wall as feature wall and larger ones on other walls ..

It can either look really dramatic or too dark, depending on the size of the room as well as your other components. I've attached a couple of images of our work using dark tiles, the smaller bathroom we have surrounded the bath with dark tiles but then balance it with an extra large mirror to bounce the light around the room. The larger bathroom we have taken the floor colour way onto the wall but used a different texture on the walls for drama. Hopefully this gives you more of an idea but you shouldn't to nervous of the room being dark, it's where you can create a contrast as well as textures. Look forward to seeing what you go with in the end.