Decorating the Classroom

How should teachers decorate their classrooms?
This is something that I have given a lot of thought to. I have seen various types of classrooms, some with neat teach work all over the walls and some with the students' work posted up to make it "their" classroom. Which one is more important? I've heard various theories.
Here is my theory. I am what you would call a "control freak". I like to have control over everything and I'm a firm believer in "if you want something done right, do it yourself". this is why I would find it hard to hand my classroom over to the students. However, I realize that as a teacher, I am an advocate for my students. My classroom isn't about me, it's about them. Therefore, if I want my classroom neat and organized the way I want it, I will do it with their work. It's a compromise. Sure, I think its important to have several encouraging posters up, but the rest needs to be the students work. I believe they will feel more comfortable with their own work displayed in their classroom; more "at home". It gives them an opportunity be proud of their work.