A huge fan of to do lists, I experimented with a number of products, including Omnifocus, Remember the Milk, even IOS Reminders, and Toodledo is really the best of the bunch. The fact that its web-based is probably the number one reason - my office uses PCs and I have a Mac at home, so an app like Omnifocus meant I always needed my iPhone at work to use it. I would add that Toodledo, with its contexts, goal chains and elegant user interface has made me a loyal user.
Rob_99 about Toodledo, v3.0.7