With these two books, we played with different kinds of closures. The first is held closed with magnets, which are embedded in the board of the cover. The second uses a flap with clasps.
I do still buy sketchbooks once in a while. Hand Book sketchbooks are a personal favorite. They're Moleskine-sized but have much nicer paper that takes watercolor paint very well.
Sketchbooks are personal for me, like visual diaries. I can often flip through a book and remember where I was, what I was doing, who I was with, and what made me want to draw what I was drawing. This one is the exception. I don't remember where I was when I looked through it. Flipping through these pages was a pleasant surprise, and I know I have never shown this one to anybody.
Here are some links to my other sketchbook posts over the years: