Unfortunately, my book is nearly full and I've been looking for another blank book of similar size. Most have lines which don't make them very nice for sketching ideas out or are significantly larger. Recently I discovered small Moleskin makes cahiers (I had to look it up. A cahiers is: "a number of sheets of paper put together for binding or bound loosely" per Webster's) that are 3 1/2 x 5 1/2". They are small, lightweight and plain boring black.
I'd seen some sweet book covers of fabric in some Japanese publications and decided to make my own. A little embroidered bunny provides a nice friendly touch! Insides a bit of lace holds the flap and sweet calico lines the linen cover. Next time, I'll make the flap just a bit longer so it holds under the lace better.
Along the same lines, I keep a sheet of cardstock at the computer to use as a blotter. Here I sketch out ideas I've seen online, take notes, cut and paste things, take phone messages or write down internet links. It keeps my work space free from a clutter of bits of paper and gives me a defined workspace. When the sheet gets full, I replace it with a new one. The old one is either discarded if filled with mundane stuff or kept in my idea file.