Web/iOS: Eisenhower is a simple and elegant way to sort your tasks. Based on the Eisenhower matrix by former US President Eisenhower, the web app and mobile app help you identify which tasks to do now, schedule for later, delegate or not do at all.
If you're familiar with time-management systems, you've probably seen this matrix before. Essentially, you add tasks into quadrants based on whether they're important/unimportant and urgent/not urgent. Something that's both urgent and important should be added to the top left box to be done right away. On the flip side, tasks that are neither important nor urgent go on the bottom right box as a reminder of what you shouldn't do. (Do-not-do lists can boost your productivity.)
The Eisenhower app takes this approach to help you evaluate and prioritise your tasks. The app is simple to use: just add your to-dos in any of the quadrants, considering whether each task is important or urgent. You can quickly add tasks and drag them around to reorder them.
I have two wishes for the web app: that the scheduling box actually had a date selector and reminders, and you could check off tasks as done rather than just delete them.
Still, if you're looking for a new task manager, or if you're a fan of this system, give Eisenhower a whirl. The iOS app is available for $1.99 (and has scheduling, a "focus mode" and syncing to the web client), while the web app is free.