I'd use the charcoal color -- you need some contrast to make the cabinets and counters pop.... and it will be much more stunning than plain white tiles -- I think the 'stunning' factor is the real resale element -- and that you've technically done the basics in 'neutrals' so individuals can add any color accessory they like

Charcoal sounds good and a bit unexpected which is always good.

Go with the charcoal. We are installing the New Yorker taupe tomorrow on a kitchen backsplash. Nice looking tile.

Charcoal but be sure to have under cabinet lighting.

unless you are selling the house next month, don't make a decision based on what the next buyer will next. You could put in a white backsplash and the next buyer may hate that. I would suggest installing a tile that enhances the space and ties all the finishes together.

I think white grout would be unnecessarily busy. The color is enough of an element without adding a lot of pattern, especially as I assume your counters have some veining you'd like to show off...