[Links updated 2008 19 03]
I recently switched from a PDA to a Filofax Personal. I find it very useful, but the refills were too poor to fit my needs.

So I made my own implementation of Allen's GTD. It is certainly not a complete set, but you'll get a bunch of '@lists' and a few others stuffs as well that I use daily. I don't think there is a need to explain how to use them ;-)

Now, there is also a few 'Project' pages which are quite specific to my needs : I work in a publishing company (monthly computer booklets), I needed a simple way to keep track of the tens of projects I am working on (as an author or as... sorry I do not know the English word : directeur de collection). Each project/book have one or more pages in wich I log every events in the notes section plus the date in the small left column. This way I keep track of the work from the begininng to the end. It is also very useful to give my boss a clear summary of all the work in progress, what is OK and what went wrong : I just need to browse trough the pages.

The PDF is designed to print 2-up on A4 paper. You will find a Letter version of the PDF (Filofax Personal templates) here :
http://davidbosman.fr/telechargements/filofax_templates_Lett...

Note that I was not able to test the printing of the Letter PDF (don't have any paper of that size).

Templates are designed to print both sides, there is space reserved for the holes, I use an Exatime '6 hole punch' (#18243 is the only ref. on its box) that fit perfectly.

I print on a B&W laser (no inkjet testing) on 60gr Clairefontaine A4 paper, which is almost as thin as the original filofax refills :)