For the people who are in a paper based system, I would highly recommend that you look at Plannerpads spiral bound or loose leaf Organizers. They can be easily adapted to the GTD methodology. It has a top section that can be filled in with your weekly activities (Next Actions) that you will monitor. The middle section is used for Scheduled To-Do's for the week. The bottom section is where you would put your appointments for that week.
The Planners come in three sizes and have several accessories that can be added inside. If you are firmly planted in the paper domain, then I would seriously look at Plannerpads.
I have no affiliation or financial interest with the company.