For a year-round bulletin board, one good idea is to use cloth for the background (because it doesn't fade like the paper does). You can use a heading like "Watch us Shine" and each month display some of the students' best
work. That way you never have to change the heading or background, all you have to do is change the papers displayed.
As far as themes, I saw a really cute one the other day that a teacher leaves up all year. It was an under-the-sea theme, each child had a fish with his/her name on it. Coming up from each fish was a big bubble. Inside the bubble, each time the student read a book,
the student wrote out or typed out on the computer the name of the book and a couple of sentences about the book, and that was cut and pasted into the bubble. I saw a similar one to this in Mailbox magazine, only it was a bathtub with bubbles.