There was a recent blog on whether or not you should have bugs (that were not found during the most recent iteration) added to your product backlog, or kept in a separate bug backlog. Here at Klocwork we have a defect database that is closely monitored by Support, dev, PM, and so on…suffice it to say, it has a high degree of visibility within the organization and will probably never go away. Being an Agile company we also have a product backlog that is reviewed daily and prioritized regularly. Every two weeks (coinciding with our iteration planning) PM and Support get together to discuss the highest priority bugs, and to determine if those bugs should/need to be added to the backlog for the next iteration. A key piece to this process is using tools to maintain this backlog. The backlog tool, which also has an integration with our defect tracking system provides a tight correlation between the two, and a level of automation that makes life a little easier for everyone. Once added, these bugs are prioritized just as we do with all of the other features (stories) we have in the backlog. We also have weekly status meetings where the most recent bugs are discussed, once again to ensure they receive the proper attention.
Since we are in the bug-finding business, we take bugs very seriously and adding them to our backlog (and as a part of our iteration planning) helps ensure we address them quickly.