Tele-Support HelpDesk has a very good and easy to use bug tracking system that also has the benefit of exposing it to the support department to link customers to the issues and then notify the customers when the issues are complete. I live in it daily, and have found the workflow to be extremely productive. Management always knows whats currently in progress, what was just fixed, and what issues are hot (and even how long something should take to get fixed).
It has a very good customizable priority system. Each issue can have a category and product assigned to it and at a button click will be organized to that list. There is a quick filter option, and the ability to do even finer filtering. With estimated time to completion it auto calcs total completion on the fly based on what is currently visible in the list.
our Typical Workflow: Bugs are entered into the system by the support staff/QA Staff. Management reviews the list of "new" bugs and sets the priority they would want them done in. Development staff looks at priority list and sets estimated effort levels. Management reviews and adjusts priority. Development completes issues. QA verifies completed issues and notifies customer upon successful update posting.
At all stages, any one in the staff can look at the list and see what the current status is, and even add notes or attach another customer to the problem. There are fields for release version, which we use with a custom filter / report to auto generate our release notes. (screen shot of open known issue: which is the bug tracking portion of the product).