This is a good article on how to modernize your bathroom. I like this article because it focuses on usability and general guidelines that are essential to a great bathroom design. Too many articles focus on details that apply very few people.
My additional tips are:
1) Use PEX, or if remodeling replace plumbing lines with PEX as far back into your system as you can get to easily. Around the plumbing fixtures you should be removing the drywall anyway, so this is your opportunity to prevent future leaks and expensive repairs. You probably don’t want to trace the lines so far as to disturb drywall in other rooms, but you should go as far as you can through access in the attic or crawl space.
2) Buy the best materials and fixtures you can afford – the installation cost of a low-grade tile is the same as high-grade tile, but the durability of the product and style can add 5-10 years to the life of your bathroom. Bathroom remodels are expensive, so it is worth a few extra dollars now to create a long-lasting room.
3) Think through your daily routine to make your bathroom efficient, don’t be limited in your mind by where things are now. Whether you are remodeling or looking at original builder plans, don’t limit yourself to the layout you see – how your family will use the space is most important.