I finished my sketchbook just before Christmas. I have another grey book on the go that I could have used, but they're not so good for the material I was going to be sketching up north on a camping trip. 
So I took this A6 concertina sketchbook that's been kicking around for a year or two. I can't remember the brand (it has a blind debossed logo embedded into it's cloth cover, but it's a tad blurry so I can't tell what it says). I quite enjoyed it, sketching in a concertina sketchbook is something I hadn't done before, but a lot of fun as it turns out.