Here is a review of several sketchbooks that you journal keepers should know about
Bear Books are great low-budget journals for teachers. Another great option for teachers is to use unruled composition books. Roaring Spring Composition Books work very well. You may also find other brands.
Kunst & Papier Sketchbooks are cool bound sketchbooks that can be folded back on themselves.
Komtrak Inspiral Notebooks allow you to add whatever type of paper that you like.