A tile supply warehouse will have a better selection of tiles to choose from, fresher setting materials, and are typically more knowledgeable when it comes to questions about their products.
As far as selecting a tile you would want either a glazed ceramic or a solid porcelain type tile (easy cleanup). Make sure the tile is smooth with no pits or crevices that will harbor dirt and grease. I would choose a size from 4"x4" to 8"x8". Also you want to make sure that you can select matching end caps.
Once the tile has been installed make sure to seal the grout after it has cured.