A third great spot to play with wallpaper....your entry/foyer! Usually a smaller area, no need to commit to the entire house. Make sure that the colors pattern blend with the rest of your house. Although I think you can go a little more wild than the rest of your home, this will set the tone of the rest of your house-give the guest an idea of what is to come. So stick with a similar theme or color scheme. Also make sure that your door turns into a great accessory for the wallpaper.
Are you a renter and so sad that you can't wallpaper your entry? Fret no more. Removable wallpaper is your friend. Some ideas below, but please read the details to make sure these will work for your situation.