HN Poll: What bug tracking software do you use?

I am thinking of a project idea related to bug tracking software, and I am trying to get a rough sense as to what are the most popular bug tracking systems. Which of the following do you use in your job/start-up:

- FogBugz - Bugzilla - Mantis - Jira - Trac - Redmine - Other (please provide name)

Also, if you could provide the rough number of users that use your particular bug tracking system installation that would be helpful.

Thanks!

PS: If someone with sufficient karma can kindly re-submit this as a proper poll, that would be great.