Jira may be extremely sluggish and require a large amount of memory on the client side.
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.
Mantis Bug Tracker - Mantis Bug Tracker is a free and open source, web-based bug tracking system.
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.
openDesktop.org - The website openDesktop.
Basecamp - A simple and elegant project management system.
SourceForge - The Complete Open-Source and Business Software Platform.