This panel presentation report is on the in-house use of virtualization technologies in large research, midsize, and public libraries. Our presenters represent a variety of backgrounds and types of libraries, and will describe how leveraging virtualization in their particular setting has led to increased capacity, while reducing costs, downtime, and management headaches. It is our hope that by sharing our virtualization successes we will broaden the discussion on when to build locally and when to move to the cloud.