I stumbled over a very interesting blog article by Ben Simon about a todo management system on paper. He was using electronic methods (e.g., Org-mode) before he switched to a clever index-card-based method. The paper-workflow he describes sounds very interesting.
Interacting with physical paper instead of computer devices is also very attractive to me. However, Org-mode offers so many advantages by now, that I can hardly switch to a paper-based method which only relates to a sub-set of the features of Org-mode.
For the future, I am hoping for some kind of electronic paper that I can sync to my Org-mode to mimic Ben's workflow and his daily review task. The DPT-S1 by Sony seems to be the best match so far. Unfortunately, it's way to expensive. There is also room for improvement for sync-methods, speed of content switching of the display, interaction with content (marking things as done, ...) and most of all: on-the-fly character recognition of hand-written notes.
So, I'm still looking for PIM improvements ...