Can you say more about this? I am in the midst of using OmniOutliner for the same thing.
Although I have a number of OO documents for various subjects, my master "To Do" document contains a large number of lists, and I use two columns, where the meaning of the second column varies depending on the section.
I start of with a "Principles" section, where I keep a number of important ideas that I want to remind myself of frequently. I don't use the second column in this section.
Then I have my "Someday Maybe" list, where I catch all of the project ideas (computer and non) that occur to me-- primarily so I can stop trying to remember them, as Allen suggests. Once an idea is in this section, I review it periodically, but I don't have to worry about remembering it or feel stressed that I'm not doing it right now. I use the second column here for category keywords.
Next is the "Projects" section where, again following Allen, that I list the projects that essentially all of my tasks fit into.
I then have a "Shopping List" section which is a sort of "Someday Maybe" list for things I'd like to buy. I often keep URLs in the notes for each item about where I've discovered a particular item for sale.
Then I have my "Waiting For" section, where I list all the things I am waiting on others to complete, and I keep "tickler dates" in the second column so I have a reminder of when to review that particular item. Items I'm waiting for include things like books others have borrowed from me, tasks delegated to others, etc. (In Eudora I also have a "waiting for" folder where I put e-mail messages to which I'm expecting a reply. I periodically review this folder as well.)
Last but not least comes my "Next Actions" section, where I list all the next actions I'm considering, and I use the second column to state the project to which each action belongs. It is from this list that I draw up my daily priorities.
I'd be interested to hear how you've gone about adapting OO for your own Getting Things Done
To understand more of what this is all about, definitely read Getting Things Done: The Art of Stress-Free Productivity
by David Allen.
BTW, version 3 of OO, especially the Pro version is A M A Z I N G.
It does look very cool. I'll give it a spin soon.