We practically run our company on bugzilla , and not because we are drowning in bugs, but because we misue it the same way so many people over extend Excel. We'd probably feel less sheepish if it was named "Listzilla" or something.

Here's what we use it for:

• Bugs (natch)
• Feature requests
• System error reporting
• Editorial calendar development
  
• Collecting and grouping ideas for future products/projects
• Workflow task collection
• Customer Management
  

And probably a few more things that are just not coming to mind right now.

If someone asked me to name the top three or four pieces of open source software, bugzilla would certainly be right up there.

And, unlike switching from Windows to Linux, switching from an email based bug tracking systems (you email Wilma, she enters it into a spreadsheet) to bugzilla takes about five minutes. Installation is a breeze and it is lightweight enough to run on a teeny old laptop off in a corner somewhere.

System Error Reporting

One of the neat things you can do with bugzilla is to use one of the many plugins and have your other systems email/ping your bugzilla with a task when something goes awry.

For example, write a cron job that greps the "error" string out of your Apache logs and email it to bugzilla and assign it to your sysop.

Feature Request

It take two minutes to train someone to use bugzilla. When you're having a meeting have someone capture every "wouldn't it be neat it" idea and assign it to a project. You can discard stuff later, but this way you don't lose killer ideas.

Future Project Ideas

Sames as with features - why not collect all those things that come up in meetings and save them as future projects that can accumulate features until they're hatchable.

Editorial Calendar Development

Once again, you can catch the ideas as they flow.  Best of all, you can assign dates to each "bug" and assign them to specific users.   You can attach files to the items.   You can give external contractors logins and they can only see their assignments.

Customer Management

 If you do projects with customers then they will report bugs.  If you can train them to enter the bug, groovy.  If not, you can give them an email address to email their bugs into bugzilla.  When the bug is fixed you can setup bugzilla to email the customer that their stuff has been fixed.   You can also generate simple lists of open and closed issues so that you can more easily manage your weekly status calls.  (You do do that don't you?)

Best of All 

This is all free.   And easy to use.  How much stuff out there makes you look good,  is easy to use, and is free.  Hooah, Bugzilla!