I finally got around to decorating the most recent journal I have been using. The Close To My Heart My Creations Journal is a great book to alter. I love that it has unlined white pages and white chipboard covers. The front cover has a clear pocket to slide your cover art into. This really helps keep your journal looking nice.
I use a journal to record ideas I want to try, rough draft journaling for layouts, and try various medium techniques. Pretty much anything I might want to remember.