There are many desktop information tools to customize your PC, but far and away the most popular is Rainmeter, an open source project run by volunteers who have created a fantastic desktop information resource.
Rainmeter uses "skins" to display information on your Windows desktop. It's not unlike the old widgets Microsoft introduced with Windows Vista, except those were hard coded and fairly basic. Rainmeter skins are basic text files that you can open up and view or change.
Rainmeter falls into three categories: system information, app launcher and information display. The app launchers are the most complicated to configure but still pretty easy to set up. It's the system information and info display aspects you could find most useful.