To Get Things Done, you don't need GTD tools
We have to realize that the book originally wasn't intended for, well, everyday people. It was written for the busy, high performance, CEO in the business world. Someone with many contacts, reports and travelling time.
Thats why we see so many different successful implementations of GTD. Lifehackers tweak the system so it fits them and the tools they have at hand. For instance using GMail or Backpack instead of Tracks or GTD TiddlyWiki. Writing in Moleskine's instead of using DIY Planner cards.
So, when you decide that GTD just might be the hack your life needs, don't start by searching for the perfect GTD tool. Build it yourself. Start with what you have in front of you and work from there. Try to fit GTD into your life, not the other way around. The chance for success is much greater, and it is much more fun.