ZeroTodos!

Todoist is a task manager thats useful, fast and easy to use.

Take your tasks anywhere with this feature-packed application.

Take quick notes on Post-It(r) like sticky notes on Windows desktop, stick those notes to websites, documents & folders. Set reminder alarm to each sticky note. To avoid desktop clutter, you can organize those sticky notes inside folders. Send sticky notes to another computer over local network (LAN) or Internet, Sync sticky notes between computers using the Notezilla.Net cloud service, access your sticky notes on any smart-device such as iOS(iPhone/iPad), Android, Windows Phone, Blackberry etc. »

A simple but effective way to keep on top of your tasks, 10 languages.

An easy to use, web-based to-do list. Get organized, stay motivated, and be more productive.

Task Coach is a well-structured, portable, open source todo / task manager (supporting 50 languages). It grew out of frustration that well-known task managers, such as those provided with Outlook or Lotus Notes, do not provide facilities for composite tasks. Over time, Task Coach has added effort tracking, budgeting, notes, priority adjusting, reminders, and many other features.

CintaNotes is an ultra-ergonomic, productivity-boosting notetaking app for Windows. It will help you collect, organize, and find any information.

RedNotebook is a graphical diary and journal helping you keep track of notes and thoughts. It includes a calendar navigation, customizable templates, export functionality and word clouds. You can also format, tag and search your entries.

TickTick is your daily must-have to-do & task list to make all things done and get life well organized.

Org-mode is for keeping notes, maintaining ToDo lists, doing project planning, and authoring with a fast and effective plain-text system.

NixNote, formerly Nevernote, is an open source client for Evernote . It is written in Java so it will also run on Windows & OS-X, but the primary focus has been to try and get a usable environment for Linux.

Track your tasks and projects in a plain text file, todo.txt. A todo.txt is software and operating system agnostic; it's searchable, portable, lightweight and easily manipulated.

EssentialPIM lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.