I agree that back splash needs to be replaced. Because of the dark cabinets, I would do something in the white-ish family and subway tile would be fine.

none of those choices are better than what you have. the only one that;s a meh is the white subway. And you want a plain white subway, why?

this is one of the few times that this type of bar tile can actually work. you have a solid gray counter, dark cabs, med dark wood floors, and you want to do a plain white subway? you have the perfect canvas to do an actual cool backsplash since everything else is subdued.

this is a beveled Calacatta marble. 2x4. but I would like it in larger tiles

like this 4x12 size

cement looking tiles

if you have to have white, at least do one w/a cool pattern. white marble in a chevron