Depends on what else is in the room. I would look at a travertine in a mid-tone and use a matching grout. Travertine comes in square or in a subway shape.

A gray glass subway tile would be very pretty with your granite.

Country Cottage Glass Subway Tiles, 10 Square Feet · More Info

A white or cream glass subway tile would look great. Since your cabinets are dark and the granite is a darker shade as well I wouldn't recommend using any darks in the backsplash as it will darken up your kitchen and in the end you will be unhappy.

We have a light cream and a bright white glass 3x6 subway tile that I linked below. If you are interested in some free samples for your kitchen just get in contact with us on our Houzz profile.

Ice White:

3"x6" Ice White Glass Subway Tile · More Info

https://www.houzz.com/products/3x6-ice-white-glass-subway-tile-prvw-vr~40060255?lid=26405656

Cream:

3"x6" Cream Glass Subway Tile · More Info

https://www.houzz.com/products/3x6-cream-glass-subway-tile-prvw-vr~40059039?lid=26404651

Hi - as mentioned above something in a medium tone or in the beige family would be a good option. Also, not sure of your budget but other options would be mosaic tile which would add interest. Look at mosaic tiles from Sonoma Tilemakers e.g. Vihara Karuna (they come in varying sizes) - they have silk and iridescent finishes. Artistic Tiles Tozen Collection Natural Vanadium or Agate Collection are also interesting - they will be different from most mosaic tiles. I do not know if you have under cabinet lighting but under cabinet lighting not only provides the proper lighting for tasks at the counter but will graze the tiles and highlight them.

Hi, i would recommend a subway tile. For more ideas, please feel free to read on: http://bit.ly/1reZQzp. Good luck!