Moleskines - if you're a writer, you gotta have one. According to moleskines.com, a moleskine "is the legendary notebook, used by European artists and thinkers for the past two centuries, from Van Gogh to Picasso, from Ernest Hemingway to Bruce Chatwin." (Yes, I agree - I never thought of Hemingway as a European artist....)
Wikipedia has a nice history of the notebook, which is currently manufactered in Italy by Modo & Modo since the original manufacturer, Tours, went out of business in 1986.
From the Modo & Modo site, "...in Ernest Hemingway's memoir, Moveable Feast, he chronicles Paris in the 1920s just after World War I while spending time writing in various Paris cafés. Hemingway reflects on the quintessential moments ordering a cafe au lait and pulling out his notebook and pencil from his pocket to start writing. It is this simple ritual that he describes so well. That comfortable feeling, when even in the mist of a bustling café that one can immerse oneself into thoughtful prose or a delicate sketch. During this time in Paris, Hemingway apparently had also been working on The Sun Also Rises using his trusted Moleskine. Not a surprising notion to those that have come to know and love Moleskine."
For how people are using their moleskines, check out Moleskinerie.com.