Everyone I know has one form or another of a to do list. I currently use my Blackberry Tasks application because its portable and easy to use. Some people like to use text files, I did so for some time. Life Hacker's Gina Trapani even developed a full scheduling system using unix scripts and a text file for Todo.txt. Others like a fully integrated system like Outlook. There are many web based systems such as Remember The Milk, iGoogle, Yahoo and many others.
A few months ago, I read a post on Zen Habits about a site called Now Do This. This is a very basic and simple list that gives you one thing to work and focus on. I've tried it and and liked it for various occasions throughout my day. When I need to really focus on a project I would use this and get a small 3 to 5 item list done and completed. All other programs on my PC would be closed except what need. When using this, when you complete your list, you get an "ALL Done" message that confirms that you've reached your goal.
I'm sure you already have your favorite to do system in place. For those who want to give something new and simple a shot, or are just curious, why not give it a whirl. It takes only a minute to setup, which is what I like about it.
What do you use to track your to do list? Have you tried Now Do This? What system do you like best?