About 6 years ago, I started putting 2X3 pieces of paper in my velcro wallet. That was when I spent most of my days with at least two pens in my shirt pocket...yeah, I know...pretty geeky!
Anyway, in the past 5 years of practicing GTD, I've realized that the tool is such a minor aspect of the Martial Art of knowledge work. What is the powerful piece IS the processing algorithm.
What's the NEXT ACTION?
What's the SUCCESSFUL OUTCOME?
Once that habit is held on to, you could quite literally collect something on a restaurant napking, trusting that eventually it would be processed into your "organizer."
How does one build up that trust? Consistency...Always write things down when you think of them. (Write them down, record them in a digital recorder, ask an assistant to take a memo...I even call my own answering machine if need be!)
Then, process those collection buckets regularly. There ARE many ways to do the individual steps, the only common demoninator is that GTD'ers do all 5 phases as individual steps. Sometimes you go really fast through all five, other days...I just want to collect!