Although I check at least once per week another computer software for GTD alike system, I always fall back to my my good ole paper system.

When you have ensured enough material of paper (cheapiest way is self production), a sorting system based on GTD (with chapter sign leaves), then nothing can stop you on organizing.

I can't take my stationary home computer everywhere with me. And my Palm, when Batteries go down it's not usuable.

But paper is always usuable, just limited at amount and ability by pen or author (myself).