Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Instagantt - Instagantt is a powerful and intuitive Gantt chart tool to enable teams to plan, manage and visualize their projects easily. Manage your schedules, tasks, timelines, and workload like a Pro. Try it for free.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Manifold - Manifold GIS is a combination of mapping, CAD, DBMS and image processing.
Asana - Asana project management is an effort to re-imagine how we work together, through modern productivity software. Fast and versatile, Asana helps individuals and groups get more done.
Kanbanier - Clean iOS and Mac kanban/trello with flexible views