I think it's important to have classroom rules and expectations up around the classroom so the students have reminders about acceptable behavior. I would probably hang this by a group work area in a classroom for a younger grade.
Help Wanted bulletin board. Pockets with classroom job descriptions. Write student names on craft sticks and place them in appropriate pocket. Fun and easy way to switch up student jobs throughout the year.
A series of posters covering all of the non-fiction genres. I've also included some basic information on writing introductions and conclusions. Perfect for on the run up to the dreaded SATs. Have included PDF file AND publisher file in case you want to.