It's important for kids to respect their parents guidance. It is a PITA to discipline kids, but they are so much better off for it. It's self-reinforcing (in both directions). Kids who get discipline and have heard "no, you cannot have that" before will not pitch a fit when they hear something they don't like.

I hate to be in the position of advocating in favor of a reality TV show, but "Super Nanny" was transformational -- it's got a handful of simple, effective suggestions for parenting.