If you find a problem with your system and think it might be a bug, use the reportbug package to check it out. This package will allow you to view bugs recorded against packages and also allow you to add a new bug report to the Debian bug reporting system.
Otherwise visit the Debian email lists at http://lists.debian.org/ and search for the problem there. The advice one gets here is generally of high quality.
In the following sections I identify a number problems or issues that I've not yet resolved for some of my installations.