About 12 years ago, I added a second journal to my arsenal of creative endeavors. I'd already been journaling daily for a number of years, as I've mentioned here before. While I'd been an on-again/off-again diarist (mostly writing in angst), after I did the Artist's Way, I started doing morning pages each day and it has become an emotional and spiritual practice as well as part of my creative work.
The second journal is what I call my creative journal. It's where I take notes at workshops or lectures, paste in quotes or good ideas, keep track of my thinking about my novels, write prompts or poetry, do lists with my groups. It's a record of the creative work in my life.
I don't use it every day but most days I put something in it, espcially once I started using it as a sort of scrap book.
Other people keep sketching journals or do visual journaling and while I do some of that in other notebooks, especially if I'm traveling, the creative journal is one I've stuck to.