I love white-walled bathrooms with blue-tiled floors. It feels clean and fresh. Our main bathroom will feature this combination, in a style that fits in a 1920s-era home. (We can't go too Moorish or too modern.)
This look is generally accomplished with encaustic cement tiles for the floor. Encaustic tiles are a very old form of tile, but they are rarely used in new construction in the US. (Our contractor has never worked with them before.) They require more maintenance and care than porcelain tiles, but they are becoming popular again in the US thanks to their vibrant patterns.