What is the best notebook?

While the product will vary between manufacturers, the sketchbook is a great tool for note-taking thanks to its very nature:

• it has to be (relatively) cheap - nobody will pay big buck for a piece of paper just to make sketches, especially when it has to be bought quite often
• it should have a good quality paper - even though they are (usually) just sketches, it doesn't mean they don't have their needs
• it should be tough - sketchbooks usually travel a lot, and they should withstand being thrown around
• there should be many options regarding types and sizes - thanks to heavily varying needs of the artists
• it's (very) plain - while it can be a nice feature to have a colorful image on it, they more often have plain covers - thanks to that they're easily customizable; their pages are plain too, giving a great flexibility for filling it with varying content.