HOPE Class - Commonplace Books

Today I had my first H.O.P.E. class. It was actually the second class, but I was very sick the first one (in fact that night was the night I was admitted to the hospital with pneumonia).
The class was about commonplace books. Honestly, before I saw the class title, I'd never even heard of a commonplace book. It's pretty simple though, a commonplace book is a place to record information, quotes, etc and your thoughts about them. By nature each person's commonplace book is going to be organized a little differently, based on what works well for them.
I am determined to start one, but how I will organize it I am less sure of. I am drawn to the appeal of a bound book, as I find books with binding easier to carry and easier to write in than binders. However, I know that I would have constant issue with the disorganization that will inevitably come from having different subjects mixed together. I'd love to have a pretty little journal type book, but I can't stand lined journal paper, and my writing is hard enough to read (even for me) with lines, let alone without them. So, I just don't know. I'm seriously considering just sticking with writing in my spiral notebooks, they are easily portable and I have lots, and then having the rings and the holes from the binding cut off just leaving the binder holes. I could then organize those pages into a binder. The problem there is that I will probably never organize those pages into the binder. There were suggestions to use different colored inks for different topics, but that would not work well for me, I'd always be using the wrong color, often subjects fit more than one category for me (another problem with the binder system), and I'd probably be losing my pens every day. I could do a bound book and keep an index at the back of the book, I think that would work if I could find a book I liked, I guess I'll have to go see what kinds of books might be available.