Not sure why, but my GTD system has just sort of clicked as of late. Everything has come together and is working in unison, a very good feeling.
I've posted this on some other GTD forums. If you'd like to take a look at how I organize my paper based GTD system, here it is:
my paper based system explained
Please share what works/doesn't work with your paper based GTD systems. Look forward to hearing/sharing ideas with you!