Lately I’ve been playing around with page numbering in my Moleskines:
A numbering stamp (the automatically advancing ones are known as "numbering machines") is a great way to personalize your blank books. It adds a new level of "craft" to the process of filling a book (especially since many of the more affordable ones require you to ink your own pads!), and also makes it easier to add references, such as a table of contents, once your book is full.
Some people question whether a numbering stamp is worth the money when you can just write your own numbers in. I appreciate the economy of this approach, but as a GTD fiend I also believe there is an inexplicable benefit conferred by mechanically created labels. This is operating on the same principle as that of using a Brother labeler for your files rather than writing on them by hand. David Allen himself couldn’t explain it very well, but there it is, and we know from experience that it works.