Comment Technology isn't always the answer. (Score 1) 278
Frankly Covey Daily Planner which uses the "Getting Things Done" methodology. Technology isn't always the best thing! It works because it's effective, and, when you're working in your planner you're not distracted by anything else be it email, websites, etc...
Your primary objective when planning is to have a singular focus on your tasks to prioritize them and follow-up on them. In my opinion, that is easier to do when you have a singular item devoted to that planning that is physical in nature.
That being said, if you absolutely want something on your computer. Check out Taskwarrior, it's open source and is based on the "Getting Things Done" methodology as well.