Customized Moleskine planner:
http://web.archive.org/web/20090429083440/http://aks-research.blogspot.com/2007/08/diary-moleskine-hack.htmlWarning: Do not go to the above site in Qupzilla v1.8.9. It will crash your system and bring you to the login prompt. Appears Qupzilla can't/doesn't want to handle the javascript errors that show in other browsers in a separate window.
For those of you in Germany or other EU countries, I've recently discovered that there is a competitor to Moleskine called Leuchtturm1917. It's supposed to be better based on one brief review that I recently read. I do know that the Leuchtturm1917 is offered in more cover colors and the pages have pre-printed numbers.
https://www.leuchtturm1917.comUpdate: Took a closer look at the Leuchtturm1917. I use notebooks with squared/graph lines for the above hack. The Leuchtturms take away space at the top of each page to allow for a date entry and also takes away space at the bottom of each page for the page number. I think I'll stick to the Moleskine notebook.