Most of my clients, both commercial and residential, ask me to specify paint colors, but I frequently encourage my clients to incorporate wallpaper, especially in powder rooms (not bathrooms where moisture can be an issue), dining rooms, and bedrooms. Wallpaper in powder rooms can create many different wonderful effects: drama and sophistication, whimsey, an outdoor/garden feeling, a cabana effect, an architecturally detailed/moulded effect, and more. Powder room ceilings are often papered to complete the look.
Dining rooms are part of the home where a bit of formality can prevail, and wallpaper can add formality much better than paint is able to. Crisp stripes, subtle damasks and beautiful florals are time tested and relevant wallpaper styles that allow significant room for creativity and provide a formal backdrop for dining room furniture, area rugs and window treatments. For more casual dining areas, wallpaper can still provide a lot of charm through color and pattern.
Bedrooms can be wonderful spaces to personalize with wall coverings. Without getting locked in to something too cute, kids' rooms allow for many different fun and colorful patterns. I generally encourage clients to choose something that seems a bit grown up - kids seem to really love it, and the selection then lasts many years. Master bedrooms, often viewed as private oases, allow for favorite colors in wallpaper or paint. Wallpaper contributes to a specific look or feeling, be it garden-like, tailored, or posh and elegant.
For commercial use, wallpaper can contribute in a big way to a customized, finished look. I've used wallpaper on numerous office projects in bathrooms, hallways, waiting rooms, and lounge areas. It adds a layer of visual interest and keeps things from being too bland. There are many commercial grade wallcovers available in terrific colors and patterns.
Although many clients are somehow under the impression that wallpaper is "out" - not sure where that comes from - I encourage using it in many projects! Here are some of my favorite vendors:
And here are a couple photos from the Thibaut website: