Very strong second
I very strongly second the previous post's recommendation of getting a fully-functioning paper system in place before doing a digital version. I base the recommendation on years of tinkering with different digital and analog "gear", trying in frustration to get it to work.
After going back to a simple file cabinet, 5x8 notebook, and 3-ring binder, my system has worked better than ever. I have also learned some of the limitations of paper as well as digital and so any change in my system has to be carefully done.
If you insisted on digital, then I would recommend plain text files and a well-organized folder structure in your computer. It is the most reliable and universal approach. Your lists can be backed up quickly and in a flash. They can be printed. They can be sync'ed more easily. There are no compatibility concerns. You can fit all of your lists on any phone and edit them on any computer.
The rest is anecdotal:
A typical scenario would be: find some new techno-gadget that promises the world. Some of the most fascinating ones were only available on operating systems I didn't own. I would then spend several days getting the new system fully in place... and then I would hit a roadblock... like I can't access the information unless I'm at my desktop, or it won't sync with my phone, or my laptop is cutting off the bottom half of each of the project plans, or there is some bug or glitch. Far too many times, I would then find that I could not export from this "new" system to the "new new" system that promises to address the bugs. In short, I could add up the time wasted just implementing systems with existing data and I would have lost months.
I've tried Onenote, Blackberry, Word documents, PDF's, plain text, Outlook, databases, digital voice recorders, spreadsheets, and tried them in both Windows and Linux environments. There was always a glitch.
Imagine my excitement when the piece of mission-critical data I needed was in a Onenote file and the only computer available did not have Onenote installed. Imagine how fun it was to learn an entire operating system, only to find that it was wholly incompatible with my phone and printer. Lastly, imagine how fun it is to rely on an Internet-based planner when you are in a rural area with no coverage, or a dead battery.
This post was longer than I intended. I wanted to show that the recommendation wasn't based on whim.
Hope this helps,
JohnV474