I like XP and Agile programming style. And I am very fond of day and week to-do lists to mark project goals achievements. I have recently started to use PivotalTraker for managing my projects tasks and recod completion velocity and I am very happy with it. I use it as a companion to the workplace Jira (old version with no extensions so a very handicaped Jira.). Therefore I am using PivotalTraker as a pseudo jira extension ( when I finish a week I export the stories to CSV and paste into Jira).
I love the approach of PivotalTraker and also is good that it is easy to import/export data. Also it has perl bindings to its API: WWW-PivotalTracker . I will try it soon.