Libraries aggregate like content in different locations
Windows 7 introduces Libraries, which are virtual folders that provide easy access to related content, regardless of its location on your PC or even on your network. While the OS will ship with several preset Libraries (Documents, Music, Photos, Video) based on file type, you can create additional Libraries based on criteria you set, such as music genre or photos created on a specific date.
User Account Control Slider gives you greater control over security settings
Vista's famously annoying User Account Control becomes less annoying: It now lets you control which potential security risks it alerts you to, and which ones it lets slide.
Windows Solution Center replaces pesky systray balloons
The new Windows Solution Center lets you review notifications about potential system problems at your convenience, rather than when you're in the middle of doing something else.