Data protection is a key feature of Windows Home Server. You can automatically back up each client PC on your network daily, or however often you'd like. Home Server is smart enough to only back up files that have changed from day-to-day, saving you storage space. You can also set it to perform redundant backups if your server has multiple hard drives. That way if one server hard drive fails, you won't lose your most important data.
Photo credit: CNET Networks