Windows 8 lets you pick quite a few different things to sync between your PCs, including personalization like desktop themes, wallpapers, and your account picture, app passwords, language preferences, and more.
For bonus points, you can also tell Windows to not perform this sync (and other actions) over “metered connections” like mobile tethering with your smartphone.
You can get here from the Start screen. Move your mouse to the lower or upper right corner, then choose Settings from the bar that appears, and finally the Sync your settings section.