If your choice for aesthetics leans toward the polished, contemporary look, then choosing a polished natural stone is going to be the best choice for your kitchen. You can choose to go with a dark natural stone that matches the tones already established, such as with a black granite, or you can run a contrasting polished stone, such as a cream marble. The reflective sheen of polished tiles will complement your countertops and cabinets regardless of the color.
The rustic appeal of tumbled stone is one that can apply itself to any type of kitchen where you are aiming for a charming aesthetic over a polished, modern look. While you may use dark tumbled stones, it is most common to use a contrasting type of natural stone to help bring out the natural beauty. However, if you prefer a same-colored work area where your cabinets and countertops blend into the backsplash, you can use darker stones.
Glazed ceramic tiles come in a huge variety of colors, shapes and sizes. You could choose to run 12-inch tiles on a straight lay pattern around the backsplash, with a matching pattern on the kitchen floor. Or you could run an 8-inch tile on a diagonal, with a custom inset in the back wall above the stove. With a nearly limitless selection available, it really depends on what type of look you are going for.
If you want a rough, outdoorsy feel to your kitchen, Saltillo tiles are a natural choice, given that they are fired from clay and contain a number of natural imperfections created during the baking process. You can purchase hand-painted Saltillo tiles where each tile has a repeating pattern, or you can purchase a custom-designed and hand-painted pattern that spans a section of tiles, such as with a mural or an extended scene that wraps around your entire backsplash.