Moleskine Hacks can be found all over the web. Many of these hacks follow or personalize David Allen's GTD paradigm. I've been using a Moleskine for eight years. It's taken me several years to develop a systemic framework that I find useful. I'm always tinkering but here are the basics of my personal Moleskine system.
The first ten pages or so are dedicated to the following topics (in no particular order)...
Long-Term Projects
Books/Authors to consider
CD's/Songs to purchase or download
Movies to put in my Netflix Queue
Gift List
Blog Ideas
Vids to download from YouTube to my iPod
New Restaurants I frequented during the calendar year
Movies I saw at the theater in the calendar year (including a 5-Star rating system)
New Year's Resolutions
Books I read during the calendar year.
The rest of my Moleskine is journal form. I write just about everyday even if it's just a line or two. Interspersed are poems, haikus, short stories, sermon ideas, sketches, mind-maps, interesting quotes, etc...
On Sundays I write a weekly to-do/goal/action list on the top half of a page. I draw a horizontal line that bifurcates the page midway down. I label the bottom half ideas or miscellaneous. I don't make use of the GTD sticky tab methodology because these action lists are easily referenced since my Moleskine entries are in chronological order. The action list page is always near the end of the written pages.
I couldn't go hardcore GTD. It's just too regimented for my free-form tastes. However, I much prefer the Moleskine to the Hipster PDA which is just too chaotic for me. Any of these paper-based systems are much more preferable to an electronic PDA which I used for several years. I do use my cellphone for my scheduling and calendar since I finally have a phone with a qwerty keyboard.
BTW: I favor the Plain Pocket Moleskine notebook.