Bathroom Interior Design are base on individual needs, everyone uses bathrooms every day. So, it's good reason to have a well designed and decorated bathroom space because not only for aesthetic reasons but for ergonomics and functionality.
Now days, bathrooms are very dependent on electricity as well as water and of course it will take much budget for you to make a project luxury bathroom's design. If you want to build a new house, try to create some ideas for your bathroom such as how the bathroom's look and style. May be you want to make it romantic bathroom's style, so it's need special color such as the wall, lights, nice cabinet's design and better if you can put a jacuzzi to take bath ;-)
Many of furniture are design for bathroom use, and you can choose them to make your bathroom look nice and put all item that may you use in the bathroom. Interior Design for Bathroom also according to what size the bathroom do you have, then you can decide what kind of you want needs, design layout.