cPanel is the industry's leading Linux website control panel. You can do everything from management of your files to viewing error logs, managing email accounts and much more. cPanel's admin end (WHM) allows you to manage everything from cPanel Accounts, to Server Settings and much more. For pretty much anything you could need to do, WHM will let you do it. There are also a number of addons available for cPanel/WHM to enhance the user experience.
You can learn more about cPanel by visiting their website here.