Here's a decent short article on why you need to prime your walls, so you don't end up with the awful mess the previous homeowners left me.

DEAR TIM: I was thinking of wallpapering several rooms in my house and installing a few borders in others. But after talking with some friends who have removed wallpaper from their houses I think I might not do it. As they removed the paper they ruined their walls. The paper facing on the drywall was ripped off! Is there a way to prevent this? What can my friends do to restore their drywall? Darcey R., Brookville, IN

My Post Appraisal blog entry shows how bad the wall looked after removing the wallpaper.