Jenkins would naturally be used for automatic build/deployment/testing and reporting activities. However, would it be a bad practice to manage all environment -related activities in Jenkins as well? We did this sort of with Microsoft Team Foundation Server. We had automatic build/deploy/test activities, but we also managed our database and application deployment activites from TFS too. So if I needed to re-build a specific database, instead of running a manual script that deploys the database, I would just "right-click-and-run" the database deployment. Same thing with testing; if I needed to run a bunch of UI tests, I would just start the UI testing build activity.
However, I am unsure whether this is a good practice in Jenkins, and whether it would be a good idea anyway :) To my understanding Jenkins can use Ant, so it would be very easy for us to execute individual Ant targets through Jenkins.