My answer was serious. I've tried computer "to do lists" many times. None are as fast, convenient, accessible, or inexpensive as a simple notebook and a pen. Sometimes the best solution does not involve a computer.
I rewrite my tasks each day. This tends to have the side effect of making me complete those nagging little ones that sometimes seem stay forever.
To prioritize, I just put a little star next to the important tasks. I tried using different color inks and annotating with categories in the past but found this to be a waste of time.
It is a permanent record that I don't have to worry about backing up. I've got notebooks going back over 20 years now.
I guess one down side is that one cannot data mine it, I question the actual usefulness of such an activity.
I've tried pen and paper and it doesn't work well for me.
I have no time or desire to rewrite my tasks every day. There are literally hundreds of them, each with tens or hundreds of sub-tasks needing to be finished before the main task is considered complete.
Basically I want to use a computerized system because I believe that it will be far faster, easier and more flexible for me.