Mylar is a new Eclipse extension for associating parts of a project with different specific tasks. You inform Mylar as to which task you are working on, and Mylar learns to associate project resources with tasks stored in Bugzilla (best support), Trac, and JIRA repositories. I set up Milar to use local tasks that are stored with my Eclipse workspace - when collaborating with other developers, sharing tasks with Bugzilla is the way to go.
Switching tasks (either local or stored in a Bugzilla repository) is quick, and automatic hiding of project files and resources in Milar's "focused UI" helps reduce the overload of information that a programmer needs to deal with. So far, I have only used local tasks and Ruby projects but from the documentation, Milar should work the same for Java, Python, etc. development in Eclipse.
Great idea and well implemented!