Here is my 2011 system so far. This system is in its infancy and, as we all know, is subject to change. But so far I'm really liking it!
My main planner is my Moleskine weekly vertical, which you can read all about here. With its monthly and weekly views, this planner wins the prize for forward-planning and structuring my week.
For overflow on very busy days, I bust into my Pocket size day per page Moleskine planner. This is the third year in a row I've used a pocket size planner for this purpose (1st year I used an Exacompta Daily Pocket, last year I switched to a Moleskine daily pocket for the hard cover and elastic strap. This year the Exacompta Daily Pocket does come in a cover with elastic strap, but this version is not available here in the UK.).
This system is vastly different from my failed Daily + Weekly experiment. In that system I used my daily as a satellite to my weekly, and tried to use both at the same time as my main planner. The way I use my Pocket daily Mole is simply as that day's To Do list with any appointments filled in. I don't use it for future planning at all. That morning (or the night before to get it out of my mind) I write everything I have to do that day. The small page size limits me to what I can actually accomplish that day, and the small book fits in my pocket to go with me everywhere on days when I'm feeling really scattered so I can capture those fleeting thoughts and tasks before I forget them. Most days I don't use this planner at all, but when I do need it it's a very important capture device. Really it's a way of keeping my daily To Do lists in a bound book instead of on a scrap of paper that gets thrown away later.
My Extra Small Daily Moleskine planner is for fun things only. Specifically, it's for things I want to write in my journal later. The Extra Small is so tiny I can take it with me everywhere to capture those cute things my kids said, or anything I want to remember to expand on in my journal later.
Quo Vadis Habana notebook with white paper and blank pages. I regret to inform you that this notebook has been discontinued, QV will replace these with the ivory-paper Habanas that are currently available in Europe. But, there has been such an outcry from Habana lovers (myself included) that it's possible QV may reconsider and offer the white-paper Habanas as a special edition. I hope they do! You can read more about that here on the Quo Vadis blog's post about it.
As always, this method is subject to change! ;)