Here's a list of the main feature teams for Windows 7:
Applets and Gadgets Assistance and Support Technologies Core User Experience Customer Engineering and Telemetry Deployment and Component Platform Desktop Graphics Devices and Media Devices and Storage Documents and Printing Engineering System and Tools File System Find and Organize Fundamentals Internet Explorer (including IE 8 down-level) International Kernel & VM Media Center Networking - Core Networking - Enterprise Networking - Wireless Security User Interface Platform Windows App Platform