My own bathroom (which you can see here) is serene with white walls, wood and brown colored floor tiles. But if I wanted to add some color to a bathroom I would definitely go for blue or sea green tiles. I love the turquoise colored tiles in this bathroom featured above! The name of tiles with this shape is fish scale tiles. The tiles in the 5th images are from Fired Earth (you can see more about this brand in this previous post). Glass mosaic tiles in various shades of blue and green are also a great option. These are available from Bisazza. You can see more blue colored Mediterenean tiles in this post.
These tiles are from Fired Earth, you can see more in this previous post.